[Users] User Realm on Location table

[Edson]

Hi...

I have to manage several domains on a same SIP server, but there is a policy
that prohibit/block inter-domain calls. 

Consider A at a.a, B at a.a and B at b.b. Now suppose that A at a.a wants to call B at a.a.
But B at a.a is not connected and B at b.b is. After a 'lookup("location")', the
RURI returned is B at b.b and that is not the user wanted. 

Location table has a column named 'Domain', but it's allways empty. How to
populate this column? How to use it (make 'lookup' consider it)? And how to
prevent A at a.a calling B at a.a to reach B at b.b?

Edson