I'm getting all Users from specific UserGroups like this:
$criteria = craft()->elements->getCriteria(ElementType::User);
$criteria->groupId = array(1, 3);
$users = $criteria->find();
But how can I additionally fetch all admin Users?
I tried to add the admin attribute, but this hasn't changed anything:
$criteria->admin = array(false, true);
I assume that's because the ElementCriteriaModel has to match all attributes, but there isn't an admin which has a UserGroup with the ID 1 or 3. But how can I tell the criteria to perform a "OR" fetch?
P.S. I know I could merge two fetched criterias but I want to use a "clean" solution.