diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 4d05298..3910415 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         # run 3 copies of the current job in parallel
-        containers: [1, 2, 3]
+        containers: [1, 2, 3, 4, 5, 6]
     steps:
       - name: Checkout
         uses: actions/checkout@v4