public function unlink($groupId, $contentTypeId, $status)
    {
        $groupCount = $this->contentTypeGateway->countGroupsForType($contentTypeId, $status);
        if ($groupCount < 2) {
            throw new Exception\RemoveLastGroupFromType($contentTypeId, $status);
        }

        $this->contentTypeGateway->deleteGroupAssignment($groupId, $contentTypeId, $status);
        // @todo FIXME: What is to be returned?
        return true;
    }