Group Sharing with LDAP

Hi Guys,

I have set up my open fire with zimbra LDAP which is fetching users properly. However I see a confusion with groups as whatever users are created I see those many group are created, is it normal?

Also, if I am integrating with LDAP, how do I enable Groups and Sharing of Groups.

As well as I need to setup registration properties so that all the users will automatially be a part of one group so that when those user logs in they will be part of that group and can see all other members. Since once integrated with LDAP/AD it is not possible to create groups wondering how can I implement the above scenario?