Help me configure freeradius

This is what i whant to do: I have a wireless AP and and a linux server connected with a cat5 cable. I then have a number of diffrenet wireless users that should be able to talk to the linux server But they should not be able to listen in on each other. they should not need a password or

skip authentication

Is it possible to authorize users without authenticating them first? - List info/subscribe/unsubscribe? See http://www.freeradius.org/list/users.html