Under Configuration> Advanced Services> Airgroup> Policy, you need to enter the wired mac address of that AppleTV and then under "Associate Server With" you need to enter either the ap-name, or ap-group. Anyone associated to that ap-name or ap-group will be able to see that wired AppleTV device. Click on Neighborhood if you want other users on other APS neighboring that AP to also be able to see that AppleTV (you are not always associated to the AP directly in the room). This is all available without using ClearPass, btw.
The direct answer to your question is, that you can trunk the wired VLAN with those AppleTVs to the controller and it will advertise to everyone, or you can manually enter the mac address and it will constrain it to only users who are associated to that AP, ap-group, or neighboring that ap and ap-group.
I hope that even helps...