clients.conf with MAC-address .

Greetings, We are trying to authenticate user request coming from many APs. The plan is to authenticate the APs as well as the users centrally using freeradius. We were hoping if we could configure clients.conf with MAC-address instead of IP address for every AP. This will ensure MAC-address with shared secret to be unique and thus APs will be authenticated. Is this possible ? Any help or direction is appreciated. Thanking you, Andy.