[Alan Anderson]

If you want the LED to be controllable from both cases, you don't want to put it inside the case structure. You want the LED to be outside, with a tunnel output from the case to the LED, and the false case just needs to connect a false constant to it.

I really don't understand your goal here, though. Can you describe the desired action in terms of what it needs to do, leaving out any mention of how you want to do it?