private function processParentRelation(Schema\Relation $relation)
    {
        $prefixRegex = '/^'.preg_quote($this->name, '/').'\.(\d+\.)*(?P<sub>.*)/';
        if (!preg_match($prefixRegex, $relation->getLocalProperty(), $matches)) {
            return null;
        }

        $clone = clone $relation;
        $clone->setLocalProperty($matches['sub']);
        return $clone;
    }