diff --git a/.github/workflows/update_primary_nginx.yml b/.github/workflows/update_primary_nginx.yml
index 2b2deb7..ef8e83a 100644
--- a/.github/workflows/update_primary_nginx.yml
+++ b/.github/workflows/update_primary_nginx.yml
@@ -20,6 +20,16 @@ jobs:
       - name: Check environment variables
         run: env
 
+      # Precompute DEV_PORT_PREFIX, STAG_PORT_PREFIX, and PROD_PORT_PREFIX
+      - name: Compute port prefixes
+        run: |
+          DEV_PORT_PREFIX="${PORT_PREFIX}${GROUP_ID}${DEV_POSTFIX}"
+          STAG_PORT_PREFIX="${PORT_PREFIX}${GROUP_ID}${STAG_POSTFIX}"
+          PROD_PORT_PREFIX="${PORT_PREFIX}${GROUP_ID}${PROD_POSTFIX}"
+          echo "DEV_PORT_PREFIX=${DEV_PORT_PREFIX}" >> $GITHUB_ENV
+          echo "STAG_PORT_PREFIX=${STAG_PORT_PREFIX}" >> $GITHUB_ENV
+          echo "PROD_PORT_PREFIX=${PROD_PORT_PREFIX}" >> $GITHUB_ENV
+
       # Use sed with a different delimiter (|) to avoid issues with forward slashes
       - name: Create temporary nginx config file
         run: |