Hi Chip,
Basically, the answer is "no". You would have to plug things in under normal circumstances.
The only way around it would be a major hassle, but doable: you would need to buy Y-cables
or switches for whatever it is you have hooked up to the RRC. A Y-cable for a paddle or speaker
should be no problem, but probably not for a microphone. There are some companies making
switches to toggle microphones between two rigs, so that would be your best bet there.
For CAT, you can use a trick by enabling COM1 to duplicate COM2 (mode-6 or 7) and pulling CAT
off the RRC locally (not that the radio RRC's COM1 pinout is "backwards", so look at the manual).
If you are already using COM1 for syncing another device, then you can try a serial Y-cable and see
if it works, or go to a solid solution like the N6TV S-Box:
https://www.kkn.net/~n6tv/S-BOX/index.htmlEither way, it will not be easy, but you can get it done with some effort and expense.
73,
Mitch DJ0QN / K7DX