Hmm, if I understand correctly, if you want just an "active" frequency and no standby at all, you need to adjust the aircraft.cfg of your chosen aircraft to have no standby frequency on the particular radio.
I dont know for sure how the panel you showed a pic of should work - the switch on the middle? What does it do? Does the radio have active and standby, but you just choose between nav and com with the switch? Or..?
In any case, more complex logic can be done wiht the fsbus CCC system.
Hopefully this helped at least a bit
//Tuomas