diff --git a/matflow/data/template_components/environments.yaml b/matflow/data/template_components/environments.yaml
index a3d9f973..be0749fe 100644
--- a/matflow/data/template_components/environments.yaml
+++ b/matflow/data/template_components/environments.yaml
@@ -1,4 +1,6 @@
 - name: null_env
+  specifiers:
+    is_built_in: true
   doc: Default system environment with no special settings. Used for tests.
 # - name: python_env
 #   executables:
diff --git a/matflow/data/workflows/subset_simulation_toy_model.yaml b/matflow/data/workflows/subset_simulation_toy_model.yaml
index 9e637c30..2fb0f1fc 100644
--- a/matflow/data/workflows/subset_simulation_toy_model.yaml
+++ b/matflow/data/workflows/subset_simulation_toy_model.yaml
@@ -19,6 +19,8 @@ tasks:
     inputs:
       dimension: 200
     repeats: 100 # num_samples
+    groups:
+      - name: all
   - schema: system_analysis_toy_model
     inputs:
       dimension: 200
diff --git a/matflow/data/workflows/subset_simulation_toy_model_ACS.yaml b/matflow/data/workflows/subset_simulation_toy_model_ACS.yaml
index 69aaa217..93e86344 100644
--- a/matflow/data/workflows/subset_simulation_toy_model_ACS.yaml
+++ b/matflow/data/workflows/subset_simulation_toy_model_ACS.yaml
@@ -24,6 +24,8 @@ tasks:
     inputs:
       dimension: 200
     repeats: 1000 # num_samples
+    groups:
+      - name: all
   - schema: system_analysis_toy_model
     inputs:
       dimension: 200
diff --git a/matflow/data/workflows/subset_simulation_toy_model_CS.yaml b/matflow/data/workflows/subset_simulation_toy_model_CS.yaml
index 6e93369c..4bd80abb 100644
--- a/matflow/data/workflows/subset_simulation_toy_model_CS.yaml
+++ b/matflow/data/workflows/subset_simulation_toy_model_CS.yaml
@@ -19,6 +19,8 @@ tasks:
     inputs:
       dimension: 200
     repeats: 100 # num_samples
+    groups:
+      - name: all
   - schema: system_analysis_toy_model
     inputs:
       dimension: 200
diff --git a/matflow/data/workflows/subset_simulation_toy_model_two_level.yaml b/matflow/data/workflows/subset_simulation_toy_model_two_level.yaml
index 951031ff..c59895d6 100644
--- a/matflow/data/workflows/subset_simulation_toy_model_two_level.yaml
+++ b/matflow/data/workflows/subset_simulation_toy_model_two_level.yaml
@@ -24,6 +24,8 @@ tasks:
     inputs:
       dimension: 200
     repeats: 100 # num_samples
+    groups:
+      - name: all
   - schema: system_analysis_toy_model
     inputs:
       dimension: 200