xpdoQuery where condGroup, with OR condition

		$query->where(array(	
		 	'userId' => $ownerId,
			'class' => 'post'
		), xPDOQuery::SQL_AND,null,1);  

		$query->andCondition(array(
		 	'relatedToUserId' => $ownerId,
			'class' => 'comment'
		), null,2);

 WHERE ( `act`.`userId` = '171' AND `act`.`class` = 'post' ) AND ( `act`.`relatedToUserId` = '171' AND `act`.`class` = 'comment' ) 

 WHERE ( `act`.`userId` = '171' AND `act`.`class` = 'post' ) OR ( `act`.`relatedToUserId` = '171' AND `act`.`class` = 'comment' ) 

foreach ($conditions AS $i => $condition) {
	$where= $query->buildConditionalClause($condition,xPDOQuery::SQL_AND);
	$query->where($where, xPDOQuery::SQL_OR,null,$i);
}

<?php
$query->where("(`act`.`userId` = :userid AND `act`.`class` = :class ) OR ( `act`.`relatedToUserId` = :userid2 AND `act`.`class` = :class2 )");
$query->prepare(array(
    'userid' => array('value' => $userId, 'type' => PDO::PARAM_INT)
    ,'class' => array('value' => 'modDocument', 'type' => PDO::PARAM_STR)
    ,'userid2' => array('value' => $userId, 'type' => PDO::PARAM_INT)
    ,'class2' => array('value' => 'modDocument', 'type' => PDO::PARAM_STR)
));
?>