diff --git a/Form/DataTransformer/CustomFieldsGroupToIdTransformer.php b/Form/DataTransformer/CustomFieldsGroupToIdTransformer.php
new file mode 100644
index 000000000..662ef42f1
--- /dev/null
+++ b/Form/DataTransformer/CustomFieldsGroupToIdTransformer.php
@@ -0,0 +1,66 @@
+<?php
+
+namespace Chill\CustomFieldsBundle\Form\DataTransformer;
+
+use Symfony\Component\Form\DataTransformerInterface;
+use Symfony\Component\Form\Exception\TransformationFailedException;
+use Doctrine\Common\Persistence\ObjectManager;
+use Chill\CustomFieldsBundle\Entity\CustomFieldsGroup;
+
+class CustomFieldsGroupToIdTransformer implements DataTransformerInterface
+{
+    /**
+     * @var ObjectManager
+     */
+    private $om;
+
+    /**
+     * @param ObjectManager $om
+     */
+    public function __construct(ObjectManager $om)
+    {
+        $this->om = $om;
+    }
+
+    /**
+     * Transforms an custom_field_group to a string (id)
+     *
+     * @param  CustomFieldsGroup|null $customFieldsGroup
+     * @return string
+     */
+    public function transform($customFieldsGroup)
+    {
+        if (null === $customFieldsGroup) {
+            return "";
+        }
+
+        return $customFieldsGroup->getId();
+    }
+
+    /**
+     * Transforms a string (id) to an object (CustomFieldsGroup).
+     *
+     * @param  string $id
+     * @return CustomFieldsGroup|null
+     * @throws TransformationFailedException if object (report) is not found.
+     */
+    public function reverseTransform($id)
+    {
+        if (!$id) {
+            return null;
+        }
+
+        $customFieldsGroup = $this->om
+            ->getRepository('ChillCustomFieldsBundle:customFieldsGroup')->find($id)
+        ;
+
+        if (null === $customFieldsGroup) {
+            throw new TransformationFailedException(sprintf(
+                'Le group avec le numéro "%s" ne peut pas être trouvé!',
+                $id
+            ));
+        }
+
+        return $customFieldsGroup;
+    }
+}
\ No newline at end of file