Ah, yes, that would be a good use. I had thought you were asking it to be additive (any token selected) whereas this use would be subtractive (of all the tokens I control, only use this one)
There are some API scripts that can do what you are asking for, and automatically. I have a token mod command that swaps vision for one of my players between him and his familiar, that could be done more easily with what you are describing. But nothing I can think of at the Plus level. It could be done manually be setting and unsetting positions on the dummy account, but that would be an unrealistic amount of work.