diff --git a/.github/actions/get-userenvs/action.yml b/.github/actions/get-userenvs/action.yml
index f6652bd..7a49b4c 100644
--- a/.github/actions/get-userenvs/action.yml
+++ b/.github/actions/get-userenvs/action.yml
@@ -4,6 +4,10 @@ inputs:
   rickshaw-directory:
     description: "Where is the rickshaw repository to query for userenvs"
     required: true
+  userenv-filter:
+    description: "A filter to determine which userenvs should be included"
+    required: false
+    default: "all"
 outputs:
   userenvs:
     description: "The list of userenvs that were found"
@@ -13,8 +17,8 @@ runs:
   steps:
     - name: "Validate rickshaw-directory"
       shell: bash
-      run: ${{ github.action_path }}/validate-inputs.sh ${{ inputs.rickshaw-directory }}
+      run: ${{ github.action_path }}/validate-inputs.sh ${{ inputs.rickshaw-directory }} ${{ inputs.userenv-filter }}
     - name: "Generate userenvs list"
       id: generate-userenvs-list
       shell: bash
-      run: ${{ github.action_path }}/generate-userenv-list.sh ${{ inputs.rickshaw-directory }}
+      run: ${{ github.action_path }}/generate-userenv-list.sh ${{ inputs.rickshaw-directory }} ${{ inputs.userenv-filter }}
diff --git a/.github/actions/get-userenvs/generate-userenv-list.sh b/.github/actions/get-userenvs/generate-userenv-list.sh
index b0e9ad2..f614549 100755
--- a/.github/actions/get-userenvs/generate-userenv-list.sh
+++ b/.github/actions/get-userenvs/generate-userenv-list.sh
@@ -3,6 +3,8 @@
 # vim: autoindent tabstop=4 shiftwidth=4 expandtab softtabstop=4 filetype=bash
 
 rickshaw_directory=${1}
+userenv_filter=${2}
+
 excludes="stream8-flexran rhel-ai"
 
 if pushd ${rickshaw_directory}; then
@@ -12,10 +14,22 @@ if pushd ${rickshaw_directory}; then
         new=( "${userenvs[@]/$ex}" )
         userenvs=$new
     done
-    userenvs_json="[\"default\","
-    for userenv in ${userenvs}; do
-        userenvs_json+="\"${userenv}\","
-    done
+    userenvs_json="["
+
+    case "${userenv_filter}" in
+        "all"|"minimal")
+            userenvs_json+="\"default\","
+            ;;
+    esac
+
+    case "${userenv_filter}" in
+        "all"|"unique")
+            for userenv in ${userenvs}; do
+                userenvs_json+="\"${userenv}\","
+            done
+            ;;
+    esac
+
     userenvs_json=$(echo "${userenvs_json}" | sed -e "s/,$//")
     userenvs_json+="]"
     echo "userenvs_json=${userenvs_json}"
diff --git a/.github/actions/get-userenvs/validate-inputs.sh b/.github/actions/get-userenvs/validate-inputs.sh
index d09d9f0..003f45d 100755
--- a/.github/actions/get-userenvs/validate-inputs.sh
+++ b/.github/actions/get-userenvs/validate-inputs.sh
@@ -3,6 +3,7 @@
 # vim: autoindent tabstop=4 shiftwidth=4 expandtab softtabstop=4 filetype=bash
 
 rickshaw_directory=${1}
+userenv_filter=${2}
 
 if ! pushd ${rickshaw_directory}; then
     exit 1
@@ -10,8 +11,19 @@ fi
 
 if [ -f rickshaw-run -a -d userenvs ]; then
     ls -l userenvs/*.json
-    exit 0
 else
     ls -l
     exit 1
 fi
+
+case "${userenv_filter}" in
+    "all"|"minimal"|"unique")
+        echo "valid userenv-filter: ${userenv_filter}"
+        ;;
+    *)
+        echo "invalid userenv-filter: ${userenv_filter}"
+        exit 1
+        ;;
+esac
+
+exit 0
diff --git a/.github/workflows/core-crucible-ci.yaml b/.github/workflows/core-crucible-ci.yaml
index 5438d62..24135f7 100644
--- a/.github/workflows/core-crucible-ci.yaml
+++ b/.github/workflows/core-crucible-ci.yaml
@@ -23,6 +23,10 @@ on:
       github_workspace:
         required: true
         type: string
+      userenv_filter:
+        required: false
+	type: string
+	default: "all"
     secrets:
       registry_auth:
         required: false
@@ -127,6 +131,7 @@ jobs:
       uses: ./crucible-ci/.github/actions/get-userenvs
       with:
         rickshaw-directory: "./rickshaw"
+	userenv-filter: ${{ inputs.userenv_filter }}
     - name: run get-scenarios-github
       id: get-scenarios-github
       uses: ./crucible-ci/.github/actions/get-scenarios
diff --git a/.github/workflows/test-core-crucible-ci.yaml b/.github/workflows/test-core-crucible-ci.yaml
index 37e4cba..f84fb43 100644
--- a/.github/workflows/test-core-crucible-ci.yaml
+++ b/.github/workflows/test-core-crucible-ci.yaml
@@ -19,12 +19,18 @@ jobs:
       fail-fast: false
       matrix:
         repos:
+        - subproject: "CommonDataModel"
+          subproject_dir: "CommonDataModel"
+          branch: "master"
+          userenv_filter: "minimal"
         - subproject: "rickshaw"
           subproject_dir: "rickshaw"
           branch: "master"
+          userenv_filter: "all"
         - subproject: "crucible"
           subproject_dir: "crucible"
           branch: "master"
+          userenv_filter: "unique"
     uses: ./.github/workflows/core-crucible-ci.yaml
     with:
       ci_target: "${{ matrix.repos.subproject }}"
@@ -33,6 +39,7 @@ jobs:
       crucible_ci_test: "yes"
       crucible_ci_test_branch: "${{ github.ref }}"
       github_workspace: "$GITHUB_WORKSPACE"
+      userenv_filter: ${{ matrix.userenv_filter }}
     secrets:
       ci_registry_auth: ${{ secrets.CRUCIBLE_CI_ENGINES_REGISTRY_AUTH }}
       quay_oauth_token: ${{ secrets.CRUCIBLE_QUAYIO_OAUTH_TOKEN }}