private static function appendAdditionalNodeIDs( eZContentObject $contentObject, &$nodeIDList )
    {
        $contentObjectId = $contentObject->attribute( 'id' );
        if ( !isset( self::$additionalNodeIDsPerObject[$contentObjectId] ) )
            return;

        foreach ( self::$additionalNodeIDsPerObject[$contentObjectId] as $nodeID )
        {
            $nodeIDList[] = $nodeID;
        }
    }