run trains using 2 cab1's

I read the TMCC/Legacy thread,but nowhere does it state if two  trains can be operated on the same track/layout using one TMCC receiver (whatever it's called) and a cab1 for each train. I was thinking of the scenario of letting a guest run their train on my layout with THEIR Cab1, while I run my coal train using MY Cab1. Do we need TWO command bases, or one.............???