diff --git a/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h b/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h
index b2bfc9c7..568165ce 100644
--- a/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h
+++ b/k4EDM4hep2LcioConv/include/k4EDM4hep2LcioConv/k4EDM4hep2LcioConv.h
@@ -60,81 +60,103 @@ namespace edm4hep {
 #include <cassert>
 
 template<typename T1, typename T2>
-using vec_pair = k4EDM4hep2LcioConv::VecMapT<T1, T2>;
+using TypeMapT = k4EDM4hep2LcioConv::MapT<T1, T2>;
 
 struct CollectionsPairVectors {
-  vec_pair<lcio::TrackImpl*, edm4hep::Track> tracks;
-  vec_pair<lcio::TrackerHitImpl*, edm4hep::TrackerHit> trackerhits;
-  vec_pair<lcio::SimTrackerHitImpl*, edm4hep::SimTrackerHit> simtrackerhits;
-  vec_pair<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit> calohits;
-  vec_pair<lcio::RawCalorimeterHitImpl*, edm4hep::RawCalorimeterHit> rawcalohits;
-  vec_pair<lcio::SimCalorimeterHitImpl*, edm4hep::SimCalorimeterHit> simcalohits;
-  vec_pair<lcio::TPCHitImpl*, edm4hep::RawTimeSeries> tpchits;
-  vec_pair<lcio::ClusterImpl*, edm4hep::Cluster> clusters;
-  vec_pair<lcio::VertexImpl*, edm4hep::Vertex> vertices;
-  vec_pair<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle> recoparticles;
-  vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle> mcparticles;
+  TypeMapT<lcio::TrackImpl*, edm4hep::Track> tracks {};
+  TypeMapT<lcio::TrackerHitImpl*, edm4hep::TrackerHit> trackerhits {};
+  TypeMapT<lcio::SimTrackerHitImpl*, edm4hep::SimTrackerHit> simtrackerhits {};
+  TypeMapT<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit> calohits {};
+  TypeMapT<lcio::RawCalorimeterHitImpl*, edm4hep::RawCalorimeterHit> rawcalohits {};
+  TypeMapT<lcio::SimCalorimeterHitImpl*, edm4hep::SimCalorimeterHit> simcalohits {};
+  TypeMapT<lcio::TPCHitImpl*, edm4hep::RawTimeSeries> tpchits {};
+  TypeMapT<lcio::ClusterImpl*, edm4hep::Cluster> clusters {};
+  TypeMapT<lcio::VertexImpl*, edm4hep::Vertex> vertices {};
+  TypeMapT<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle> recoparticles {};
+  TypeMapT<lcio::MCParticleImpl*, edm4hep::MCParticle> mcparticles {};
 };
 
+template<
+  typename TrackMapT = TypeMapT<lcio::TrackImpl*, edm4hep::Track>,
+  typename TrackerHitMapT = TypeMapT<lcio::TrackerHitImpl*, edm4hep::TrackerHit>>
 lcio::LCCollectionVec* convTracks(
   const edm4hep::TrackCollection* const tracks_coll,
-  vec_pair<lcio::TrackImpl*, edm4hep::Track>& tracks_vec,
-  const vec_pair<lcio::TrackerHitImpl*, edm4hep::TrackerHit>& trackerhits_vec);
+  TrackMapT& tracks_vec,
+  const TrackerHitMapT& trackerhits_vec);
 
+template<typename TrackerHitMapT = TypeMapT<lcio::TrackerHitImpl*, edm4hep::TrackerHit>>
 lcio::LCCollectionVec* convTrackerHits(
   const edm4hep::TrackerHitCollection* const trackerhits_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::TrackerHitImpl*, edm4hep::TrackerHit>& trackerhits_vec);
+  TrackerHitMapT& trackerhits_vec);
 
+template<
+  typename SimTrHitMapT = TypeMapT<lcio::SimTrackerHitImpl*, edm4hep::SimTrackerHit>,
+  typename MCParticleMapT = TypeMapT<lcio::MCParticleImpl*, edm4hep::MCParticle>>
 lcio::LCCollectionVec* convSimTrackerHits(
   const edm4hep::SimTrackerHitCollection* const simtrackerhits_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::SimTrackerHitImpl*, edm4hep::SimTrackerHit>& simtrackerhits_vec,
-  const vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mcparticles_vec);
+  SimTrHitMapT& simtrackerhits_vec,
+  const MCParticleMapT& mcparticles_vec);
 
+template<typename CaloHitMapT = TypeMapT<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>>
 lcio::LCCollectionVec* convCalorimeterHits(
   const edm4hep::CalorimeterHitCollection* const calohit_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>& calo_hits_vec);
+  CaloHitMapT& calo_hits_vec);
 
+template<typename RawCaloHitMapT = TypeMapT<lcio::RawCalorimeterHitImpl*, edm4hep::RawCalorimeterHit>>
 lcio::LCCollectionVec* convRawCalorimeterHits(
   const edm4hep::RawCalorimeterHitCollection* const rawcalohit_coll,
-  vec_pair<lcio::RawCalorimeterHitImpl*, edm4hep::RawCalorimeterHit>& raw_calo_hits_vec);
+  RawCaloHitMapT& raw_calo_hits_vec);
 
+template<typename SimCaloHitMapT, typename MCParticleMapT = TypeMapT<lcio::MCParticleImpl*, edm4hep::MCParticle>>
 lcio::LCCollectionVec* convSimCalorimeterHits(
   const edm4hep::SimCalorimeterHitCollection* const simcalohit_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::SimCalorimeterHitImpl*, edm4hep::SimCalorimeterHit>& sim_calo_hits_vec,
-  const vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mcparticles);
+  SimCaloHitMapT& sim_calo_hits_vec,
+  const MCParticleMapT& mcparticles);
 
-lcio::LCCollectionVec* convTPCHits(
-  const edm4hep::RawTimeSeriesCollection* const tpchit_coll,
-  vec_pair<lcio::TPCHitImpl*, edm4hep::RawTimeSeries>& tpc_hits_vec);
+template<typename TPCHitMapT = TypeMapT<lcio::TPCHitImpl*, edm4hep::RawTimeSeries>>
+lcio::LCCollectionVec* convTPCHits(const edm4hep::RawTimeSeriesCollection* const tpchit_coll, TPCHitMapT& tpc_hits_vec);
 
+template<
+  typename ClusterMapT = TypeMapT<lcio::ClusterImpl*, edm4hep::Cluster>,
+  typename CaloHitMapT = TypeMapT<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>>
 lcio::LCCollectionVec* convClusters(
   const edm4hep::ClusterCollection* const cluster_coll,
-  vec_pair<lcio::ClusterImpl*, edm4hep::Cluster>& cluster_vec,
-  const vec_pair<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>& calohits_vec);
+  ClusterMapT& cluster_vec,
+  const CaloHitMapT& calohits_vec);
 
+template<
+  typename VertexMapT = TypeMapT<lcio::VertexImpl*, edm4hep::Vertex>,
+  typename RecoPartMapT = TypeMapT<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>>
 lcio::LCCollectionVec* convVertices(
   const edm4hep::VertexCollection* const vertex_coll,
-  vec_pair<lcio::VertexImpl*, edm4hep::Vertex>& vertex_vec,
-  const vec_pair<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>& recoparticles_vec);
-
+  VertexMapT& vertex_vec,
+  const RecoPartMapT& recoparticles_vec);
+
+template<
+  typename RecoPartMapT = TypeMapT<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>,
+  typename TrackMapT = TypeMapT<lcio::TrackImpl*, edm4hep::Track>,
+  typename VertexMapT = TypeMapT<lcio::VertexImpl*, edm4hep::Vertex>,
+  typename ClusterMapT = TypeMapT<lcio::ClusterImpl*, edm4hep::Cluster>>
 lcio::LCCollectionVec* convReconstructedParticles(
   const edm4hep::ReconstructedParticleCollection* const recos_coll,
-  vec_pair<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>& recoparticles_vec,
-  const vec_pair<lcio::TrackImpl*, edm4hep::Track>& tracks_vec,
-  const vec_pair<lcio::VertexImpl*, edm4hep::Vertex>& vertex_vec,
-  const vec_pair<lcio::ClusterImpl*, edm4hep::Cluster>& clusters_vec);
+  RecoPartMapT& recoparticles_vec,
+  const TrackMapT& tracks_vec,
+  const VertexMapT& vertex_vec,
+  const ClusterMapT& clusters_vec);
 
+template<typename MCPartMapT = TypeMapT<lcio::MCParticleImpl*, edm4hep::MCParticle>>
 lcio::LCCollectionVec* convMCParticles(
   const edm4hep::MCParticleCollection* const mcparticle_coll,
-  vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mc_particles_vec);
+  MCPartMapT& mc_particles_vec);
 
 void convEventHeader(const edm4hep::EventHeaderCollection* const header_coll, lcio::LCEventImpl* const lcio_event);
 
-void FillMissingCollections(CollectionsPairVectors& collection_pairs);
+template<typename ObjectMappingT = CollectionsPairVectors>
+void FillMissingCollections(ObjectMappingT& collection_pairs);
 
 bool collectionExist(const std::string& collection_name, const lcio::LCEventImpl* lcio_event);
 
diff --git a/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp b/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp
index 6b7311ea..6026d81a 100644
--- a/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp
+++ b/k4EDM4hep2LcioConv/src/k4EDM4hep2LcioConv.cpp
@@ -18,10 +18,11 @@
 // Convert EDM4hep Tracks to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add LCIO Collection Vector to LCIO event
+template<typename TrackMapT, typename TrackerHitMapT>
 lcio::LCCollectionVec* convTracks(
   const edm4hep::TrackCollection* const tracks_coll,
-  vec_pair<lcio::TrackImpl*, edm4hep::Track>& tracks_vec,
-  const vec_pair<lcio::TrackerHitImpl*, edm4hep::TrackerHit>& trackerhits_vec)
+  TrackMapT& tracks_vec,
+  const TrackerHitMapT& trackerhits_vec)
 {
   auto* tracks = new lcio::LCCollectionVec(lcio::LCIO::TRACK);
 
@@ -102,7 +103,7 @@ lcio::LCCollectionVec* convTracks(
       }
 
       // Save intermediate tracks ref
-      tracks_vec.emplace_back(std::make_pair(lcio_tr, edm_tr));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_tr, edm_tr, tracks_vec);
 
       // Add to lcio tracks collection
       tracks->addElement(lcio_tr);
@@ -128,10 +129,11 @@ lcio::LCCollectionVec* convTracks(
 // Convert EDM4hep TrackerHits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add LCIO Collection Vector to LCIO event
+template<typename TrackerHitMapT>
 lcio::LCCollectionVec* convTrackerHits(
   const edm4hep::TrackerHitCollection* const trackerhits_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::TrackerHitImpl*, edm4hep::TrackerHit>& trackerhits_vec)
+  TrackerHitMapT& trackerhits_vec)
 {
   auto* trackerhits = new lcio::LCCollectionVec(lcio::LCIO::TRACKERHIT);
 
@@ -162,7 +164,7 @@ lcio::LCCollectionVec* convTrackerHits(
       }
 
       // Save intermediate trackerhits ref
-      trackerhits_vec.emplace_back(std::make_pair(lcio_trh, edm_trh));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_trh, edm_trh, trackerhits_vec);
 
       // Add to lcio trackerhits collection
       trackerhits->addElement(lcio_trh);
@@ -175,11 +177,12 @@ lcio::LCCollectionVec* convTrackerHits(
 // Convert EDM4hep SimTrackerHits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add LCIO Collection Vector to LCIO event
+template<typename SimTrHitMapT, typename MCParticleMapT>
 lcio::LCCollectionVec* convSimTrackerHits(
   const edm4hep::SimTrackerHitCollection* const simtrackerhits_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::SimTrackerHitImpl*, edm4hep::SimTrackerHit>& simtrackerhits_vec,
-  const vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mcparticles_vec)
+  SimTrHitMapT& simtrackerhits_vec,
+  const MCParticleMapT& mcparticles_vec)
 {
   auto* simtrackerhits = new lcio::LCCollectionVec(lcio::LCIO::SIMTRACKERHIT);
 
@@ -220,7 +223,7 @@ lcio::LCCollectionVec* convSimTrackerHits(
       }
 
       // Save intermediate simtrackerhits ref
-      simtrackerhits_vec.emplace_back(std::make_pair(lcio_strh, edm_strh));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_strh, edm_strh, simtrackerhits_vec);
 
       // Add to lcio simtrackerhits collection
       simtrackerhits->addElement(lcio_strh);
@@ -233,10 +236,12 @@ lcio::LCCollectionVec* convSimTrackerHits(
 // Convert EDM4hep Calorimeter Hits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+
+template<typename CaloHitMapT>
 lcio::LCCollectionVec* convCalorimeterHits(
   const edm4hep::CalorimeterHitCollection* const calohit_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>& calo_hits_vec)
+  CaloHitMapT& calo_hits_vec)
 {
   auto* calohits = new lcio::LCCollectionVec(lcio::LCIO::CALORIMETERHIT);
 
@@ -264,7 +269,7 @@ lcio::LCCollectionVec* convCalorimeterHits(
       // lcio_calohit->setRawHit(EVENT::LCObject* rawHit );
 
       // Save Calorimeter Hits LCIO and EDM4hep collections
-      calo_hits_vec.emplace_back(std::make_pair(lcio_calohit, edm_calohit));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_calohit, edm_calohit, calo_hits_vec);
 
       // Add to lcio tracks collection
       calohits->addElement(lcio_calohit);
@@ -277,9 +282,10 @@ lcio::LCCollectionVec* convCalorimeterHits(
 // Convert EDM4hep RAW Calorimeter Hits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename RawCaloHitMapT>
 lcio::LCCollectionVec* convRawCalorimeterHits(
   const edm4hep::RawCalorimeterHitCollection* const rawcalohit_coll,
-  vec_pair<lcio::RawCalorimeterHitImpl*, edm4hep::RawCalorimeterHit>& raw_calo_hits_vec)
+  RawCaloHitMapT& raw_calo_hits_vec)
 {
   auto* rawcalohits = new lcio::LCCollectionVec(lcio::LCIO::RAWCALORIMETERHIT);
 
@@ -295,7 +301,7 @@ lcio::LCCollectionVec* convRawCalorimeterHits(
       lcio_rawcalohit->setTimeStamp(edm_raw_calohit.getTimeStamp());
 
       // Save Raw Calorimeter Hits LCIO and EDM4hep collections
-      raw_calo_hits_vec.emplace_back(std::make_pair(lcio_rawcalohit, edm_raw_calohit));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_rawcalohit, edm_raw_calohit, raw_calo_hits_vec);
 
       // Add to lcio tracks collection
       rawcalohits->addElement(lcio_rawcalohit);
@@ -308,11 +314,12 @@ lcio::LCCollectionVec* convRawCalorimeterHits(
 // Convert EDM4hep Sim Calorimeter Hits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename SimCaloHitMapT, typename MCParticleMapT>
 lcio::LCCollectionVec* convSimCalorimeterHits(
   const edm4hep::SimCalorimeterHitCollection* const simcalohit_coll,
   const std::string cellIDstr,
-  vec_pair<lcio::SimCalorimeterHitImpl*, edm4hep::SimCalorimeterHit>& sim_calo_hits_vec,
-  const vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mcparticles)
+  SimCaloHitMapT& sim_calo_hits_vec,
+  const MCParticleMapT& mcparticles)
 {
   auto* simcalohits = new lcio::LCCollectionVec(lcio::LCIO::SIMCALORIMETERHIT);
 
@@ -337,7 +344,7 @@ lcio::LCCollectionVec* convSimCalorimeterHits(
       // MCParticles converted
 
       // Save Sim Calorimeter Hits LCIO and EDM4hep collections
-      sim_calo_hits_vec.emplace_back(std::make_pair(lcio_simcalohit, edm_sim_calohit));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_simcalohit, edm_sim_calohit, sim_calo_hits_vec);
 
       // Add to sim calo hits collection
       simcalohits->addElement(lcio_simcalohit);
@@ -350,9 +357,8 @@ lcio::LCCollectionVec* convSimCalorimeterHits(
 // Convert EDM4hep TPC Hits to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
-lcio::LCCollectionVec* convTPCHits(
-  const edm4hep::RawTimeSeriesCollection* const tpchit_coll,
-  vec_pair<lcio::TPCHitImpl*, edm4hep::RawTimeSeries>& tpc_hits_vec)
+template<typename TPCHitMapT>
+lcio::LCCollectionVec* convTPCHits(const edm4hep::RawTimeSeriesCollection* const tpchit_coll, TPCHitMapT& tpc_hits_vec)
 {
   auto* tpchits = new lcio::LCCollectionVec(lcio::LCIO::TPCHIT);
 
@@ -382,7 +388,7 @@ lcio::LCCollectionVec* convTPCHits(
 #endif
 
       // Save TPC Hits LCIO and EDM4hep collections
-      tpc_hits_vec.emplace_back(std::make_pair(lcio_tpchit, edm_tpchit));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_tpchit, edm_tpchit, tpc_hits_vec);
 
       // Add to lcio tracks collection
       tpchits->addElement(lcio_tpchit);
@@ -395,10 +401,11 @@ lcio::LCCollectionVec* convTPCHits(
 // Convert EDM4hep Clusters to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename ClusterMapT, typename CaloHitMapT>
 lcio::LCCollectionVec* convClusters(
   const edm4hep::ClusterCollection* const cluster_coll,
-  vec_pair<lcio::ClusterImpl*, edm4hep::Cluster>& cluster_vec,
-  const vec_pair<lcio::CalorimeterHitImpl*, edm4hep::CalorimeterHit>& calohits_vec)
+  ClusterMapT& cluster_vec,
+  const CaloHitMapT& calohits_vec)
 {
   auto* clusters = new lcio::LCCollectionVec(lcio::LCIO::CLUSTER);
 
@@ -449,7 +456,7 @@ lcio::LCCollectionVec* convClusters(
       }
 
       // Add LCIO and EDM4hep pair collections to vec
-      cluster_vec.emplace_back(std::make_pair(lcio_cluster, edm_cluster));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_cluster, edm_cluster, cluster_vec);
 
       // Add to lcio tracks collection
       clusters->addElement(lcio_cluster);
@@ -474,10 +481,11 @@ lcio::LCCollectionVec* convClusters(
 // Convert EDM4hep Vertices to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename VertexMapT, typename RecoPartMapT>
 lcio::LCCollectionVec* convVertices(
   const edm4hep::VertexCollection* const vertex_coll,
-  vec_pair<lcio::VertexImpl*, edm4hep::Vertex>& vertex_vec,
-  const vec_pair<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>& recoparticles_vec)
+  VertexMapT& vertex_vec,
+  const RecoPartMapT& recoparticles_vec)
 {
   auto* vertices = new lcio::LCCollectionVec(lcio::LCIO::VERTEX);
 
@@ -508,7 +516,7 @@ lcio::LCCollectionVec* convVertices(
       }
 
       // Add LCIO and EDM4hep pair collections to vec
-      vertex_vec.emplace_back(std::make_pair(lcio_vertex, edm_vertex));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_vertex, edm_vertex, vertex_vec);
 
       // Add to lcio tracks collection
       vertices->addElement(lcio_vertex);
@@ -521,12 +529,13 @@ lcio::LCCollectionVec* convVertices(
 // Convert EDM4hep RecoParticles to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename RecoPartMapT, typename TrackMapT, typename VertexMapT, typename ClusterMapT>
 lcio::LCCollectionVec* convReconstructedParticles(
   const edm4hep::ReconstructedParticleCollection* const recos_coll,
-  vec_pair<lcio::ReconstructedParticleImpl*, edm4hep::ReconstructedParticle>& recoparticles_vec,
-  const vec_pair<lcio::TrackImpl*, edm4hep::Track>& tracks_vec,
-  const vec_pair<lcio::VertexImpl*, edm4hep::Vertex>& vertex_vec,
-  const vec_pair<lcio::ClusterImpl*, edm4hep::Cluster>& clusters_vec)
+  RecoPartMapT& recoparticles_vec,
+  const TrackMapT& tracks_vec,
+  const VertexMapT& vertex_vec,
+  const ClusterMapT& clusters_vec)
 {
   auto* recops = new lcio::LCCollectionVec(lcio::LCIO::RECONSTRUCTEDPARTICLE);
 
@@ -616,7 +625,7 @@ lcio::LCCollectionVec* convReconstructedParticles(
       }
 
       // Add LCIO and EDM4hep pair collections to vec
-      recoparticles_vec.push_back(std::make_pair(lcio_recp, edm_rp));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_recp, edm_rp, recoparticles_vec);
 
       // Add to reconstructed particles collection
       recops->addElement(lcio_recp);
@@ -641,9 +650,10 @@ lcio::LCCollectionVec* convReconstructedParticles(
 // Convert MC Particles to LCIO
 // Add converted LCIO ptr and original EDM4hep collection to vector of pairs
 // Add converted LCIO Collection Vector to LCIO event
+template<typename MCPartMapT>
 lcio::LCCollectionVec* convMCParticles(
   const edm4hep::MCParticleCollection* const mcparticle_coll,
-  vec_pair<lcio::MCParticleImpl*, edm4hep::MCParticle>& mc_particles_vec)
+  MCPartMapT& mc_particles_vec)
 {
   auto* mcparticles = new lcio::LCCollectionVec(lcio::LCIO::MCPARTICLE);
 
@@ -684,7 +694,7 @@ lcio::LCCollectionVec* convMCParticles(
       lcio_mcp->setOverlay(edm_mcp.isOverlay());
 
       // Add LCIO and EDM4hep pair collections to vec
-      mc_particles_vec.push_back(std::make_pair(lcio_mcp, edm_mcp));
+      k4EDM4hep2LcioConv::detail::mapInsert(lcio_mcp, edm_mcp, mc_particles_vec);
 
       // Add to reconstructed particles collection
       mcparticles->addElement(lcio_mcp);
@@ -723,7 +733,8 @@ void convEventHeader(const edm4hep::EventHeaderCollection* const header_coll, lc
 // Depending on the order of the collections in the parameters,
 // and for the mutual dependencies between some collections,
 // go over the possible missing associated collections and fill them.
-void FillMissingCollections(CollectionsPairVectors& collection_pairs)
+template<typename ObjectMappingT>
+void FillMissingCollections(ObjectMappingT& collection_pairs)
 {
   // Fill missing Tracks collections
   for (auto& [lcio_tr, edm_tr] : collection_pairs.tracks) {