Displayed Groups Configuration for mod_shared_roster_ldap

Hi everyone,

I have a ready and running configuration of ejabberd via LDAP.
The system gets its roster and users from an LDAP Server.
Everything works fine so far ... each user can only see the users in his own groups and not the others ...

However there are some special groups that should be able to see each other without the users being in both groups..

Before migration to LDAP based config i used a default ejabberd setup, in which i was able to set so called
"Displayed Groups" via admin page. Since the admin page does not work with the ldap shared rosters ... is there
any way to allow some groups seeing each other? Like Filter rules? If yes, which parameter defines the viability of groups?

Best Regards