Different LDAP group authentication with different IPs

Hello all I want to run only one radiusd (no virtual server) to support my scenario, and it is like below:

From IP x.x.x.1 -> Only Allow LDAP Group A to access From IP x.x.x.2 -> Only Allow LDAP Group B to access

from the doc/ldap_howto.txt, it seems not working.... I've found in mailing lists, and the proper solution is to use huntgroups and users file. But in freeradius 2.1.x, it's not recommended to use users to do so... Is there any good solution for this sceranio? Thanks a lot stephon