diff --git a/Configuration/Metadata/ClassMetadata.php b/Configuration/Metadata/ClassMetadata.php
index 89be6ea..5b6cc71 100644
--- a/Configuration/Metadata/ClassMetadata.php
+++ b/Configuration/Metadata/ClassMetadata.php
@@ -16,6 +16,7 @@
 use Mango\Bundle\JsonApiBundle\Configuration\Relationship;
 use Mango\Bundle\JsonApiBundle\Configuration\Resource;
 use Metadata\MergeableClassMetadata;
+use Metadata\MergeableInterface;
 
 /**
  * @author Steffen Brem <steffenbrem@gmail.com>
@@ -104,6 +105,25 @@ public function addRelationship($relationship)
         $this->relationships->add($relationship);
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function merge(MergeableInterface $object)
+    {
+        if (!$object instanceof self) {
+            throw new \InvalidArgumentException(sprintf('Object must be an instance of %s.', __CLASS__));
+        }
+
+        parent::merge($object);
+
+        $this->resource = $object->getResource();
+        $this->idField = $object->getIdField();
+
+        foreach ($object->getRelationships() as $relationship) {
+            $this->addRelationship($relationship);
+        }
+    }
+
     /**
      * {@inheritdoc}
      */