If you dont want your users' jid as nickname, just provide a nickname for the specific users at the time of registration. Then issue is solved.
Here is the example.
I have a default group 'Friends', where every new users get automatically added to at the time of registration.
Now I am registering two new Users, whose details
Here, both will be added to 'Friends' group.
Jid 1's roster will be added for jid2 whose nickname Alis will be in the roster nickname field and vice versa.