diff --git a/src/Symfony/Component/Validator/Mapping/ClassMetadata.php b/src/Symfony/Component/Validator/Mapping/ClassMetadata.php
index a079454c70519..dc825e1fa9c2f 100644
--- a/src/Symfony/Component/Validator/Mapping/ClassMetadata.php
+++ b/src/Symfony/Component/Validator/Mapping/ClassMetadata.php
@@ -354,7 +354,10 @@ public function mergeConstraints(ClassMetadata $source)
                 $member = clone $member;
 
                 foreach ($member->getConstraints() as $constraint) {
-                    $member->constraintsByGroup[$this->getDefaultGroup()][] = $constraint;
+                    if (in_array($constraint::DEFAULT_GROUP, $constraint->groups, true)) {
+                        $member->constraintsByGroup[$this->getDefaultGroup()][] = $constraint;
+                    }
+
                     $constraint->addImplicitGroupName($this->getDefaultGroup());
                 }
 
diff --git a/src/Symfony/Component/Validator/Tests/Mapping/ClassMetadataTest.php b/src/Symfony/Component/Validator/Tests/Mapping/ClassMetadataTest.php
index 9538977167546..99b15aa9a4cc8 100644
--- a/src/Symfony/Component/Validator/Tests/Mapping/ClassMetadataTest.php
+++ b/src/Symfony/Component/Validator/Tests/Mapping/ClassMetadataTest.php
@@ -135,6 +135,7 @@ public function testMergeConstraintsMergesMemberConstraints()
     {
         $parent = new ClassMetadata(self::PARENTCLASS);
         $parent->addPropertyConstraint('firstName', new ConstraintA());
+        $parent->addPropertyConstraint('firstName', new ConstraintB(array('groups' => 'foo')));
 
         $this->metadata->mergeConstraints($parent);
         $this->metadata->addPropertyConstraint('firstName', new ConstraintA());
@@ -148,9 +149,13 @@ public function testMergeConstraintsMergesMemberConstraints()
             'Default',
             'Entity',
         )));
+        $constraintB = new ConstraintB(array(
+            'groups' => array('foo'),
+        ));
 
         $constraints = array(
             $constraintA1,
+            $constraintB,
             $constraintA2,
         );
 
@@ -166,6 +171,9 @@ public function testMergeConstraintsMergesMemberConstraints()
                 $constraintA1,
                 $constraintA2,
             ),
+            'foo' => array(
+                $constraintB,
+            ),
         );
 
         $members = $this->metadata->getPropertyMetadata('firstName');