That's good to know as well. Wish DJI would have controllers like the DX 9 etc. Allow us to bind multiple birds to one controller.The only caveat is that you'll need to also upgrade the controller to use it with the P4, and then you lose the P3a F switch functionality, and the mode switch is then converted to the P4 style(Sport Mode won't do anything on the P3a), and the CSC kill command in the traditional functionality. Depending upon what DJI GO version you still use with your P3A, the F modes may have all been already moved inside the DJI GO app anyway. Binding takes 20 seconds and, once the controller is upgraded, you can switch back and forth. Just bring along a small finishing nail to push the recessed linking button on each aircraft. I keep one taped to the bottom of my controller.
Thx!!