EAP-TLS certificate question

Hi all, I've install freeradius-1.1.3,use it with AP Aironet 1100 doing EAP-TLS and works very well. I still confuse about certificate, is all client certificate created under 1 root ca, can be authenticated against freeradius that started with different server certificate? is it possible to set things like this root ca ------------ / | \ / | \ / | \ server1 server2 server3 ------- ------- ------- | | | | | | client1 client2 client3 I don't want client1 to be authenticated against server2 or server3. thanks