How to manage user roster list in openfire?

We have one more issue/concern with our application that every user is in the roster list of other user.

We have one group where every new user joins and automatically added to the roster list of other user.

What we need is every user should have only 2 users in its roster list (1 user is one of our listener and one more user).

This condition we need for all of our 3000 users. That way we can reduce the cache size of roster and unneeded stanzes flow between roster list of other users.

Please help as we dont know how to do this through Openfire admin GUI or using code.