diff --git a/house_2/model.config b/house_2/model.config
index 590fa14..5df5b38 100644
--- a/house_2/model.config
+++ b/house_2/model.config
@@ -20,4 +20,11 @@
     A model of a residential house.
   </description>
 
+  <depend>
+    <model>
+      <uri>model://house_1</uri>
+      <version>1.0</version>
+    </model>
+  </depend>
+
 </model>
diff --git a/house_3/model.config b/house_3/model.config
index 1822c6d..9767b45 100644
--- a/house_3/model.config
+++ b/house_3/model.config
@@ -20,4 +20,11 @@
     A model of a residential house.
   </description>
 
+  <depend>
+    <model>
+      <uri>model://house_1</uri>
+      <version>1.0</version>
+    </model>
+  </depend>
+
 </model>