Accept users by NAS-IP-Address

Hi, I'm running version 1.1.6 against a Postgres database. In the radcheck table I check the password and sets Expiration for the users. In the nas table I have listed all the NAS that the users can connect through, and this seems to work fine. I also want the users to be member of a group, where the group gives access to some of the NAS. If I set 'NAS-IP-Address == ip_of_a_nas' in the radgroupcheck, the user can only connect through that NAS. The problem occurs when I want a group to contain several NAS. How can I make freeradius accept the login if the NAS-IP-Address from the user, is one of several listed in a group that a user is member of? reg Svend