diff --git a/workflow.py b/workflow.py
index 2e65188..9b8683a 100644
--- a/workflow.py
+++ b/workflow.py
@@ -9,11 +9,28 @@
 def main(df: pyam.IamDataFrame) -> pyam.IamDataFrame:
     """Project/instance-specific workflow for scenario processing"""
 
-    # Run the validation and region-processing
+    # initialize the codelists and region-processing
     dsd = DataStructureDefinition(
         here / "definitions", dimensions=["scenario", "region", "variable"]
     )
     processor = RegionProcessor.from_directory(path=here / "mappings", dsd=dsd)
+
+    # check if directional data exists in the scenario data, add to region codelist
+    if any([r for r in df.region if ">" in r]):
+        for r in df.region:
+            if r in definition.region:
+                continue
+            r_split = r.split(">")
+            if len(r_split) > 2:
+                raise ValueError(
+                    f"Directional data other than `origin>destination` not allowed: {r}"
+                )
+            elif len(r_split) == 2:
+                if all([_r in definition.region for _r in r_split]):
+                    # add the directional-region to the codelist (without attributes)
+                    definition.region[r] = None
+
+    # run the validation and region-processing
     df = process(df, dsd, processor=processor)
 
     # assign meta indicator for scenario "work package" category