Oppss ! Sorry, I just realize you where doing use of the plane's radios with one of the 3rd partyes software. Whith just Ts3 comms, I have no idea about how to do that... :(
Anyway the best way to have correct realistic comms in your squadron flights and override that ploblem you have is to install Aries, or Tars. You will never go back ;)
Rgds