[otrs] LDAP Customer or Agent auth via group membership

I have implemented successfully customer and agent authentication via LDAP, but I have a question about group membership. I have created a group otrs_allow_c group where all customer users reside to allow login. But in this group I want to add another group for ease of use because we have already pre-defined groups where the users reside in. I already tried but it does not work. Is it because the perld ldap module does not recursively search groups or something like that? I also made some small tutorial to implement OTRS LDAP auth, and that way I use it now. You can find it here: http://trinityhome.org/Home/index.php?wpid=95&front_id=1 Any suggestions?