Two ways to do this. Depending on what else you're ok with allowing.
inter station traffic block is under DoS settings would stop any client from talking with any other client on the same SSID. If you to any type of screen sharing to a wireless device, this could be impacted as well.
An IP based firewall policy would/could block any device at a L3 level from talking to another device based on the firewall policy configuration you put in place.
