Not My Fault!!!

If it's of any use as I recall the R/C controller/chassis sets made for the PlaRail Advance system used to have an 'A' and 'B' setting and basically you would set them to match and could then use multiple controllers/chassis at the same time.  Basically the A/B sets it to a different radio band similar to what you get on many radio control cars so you can have siblings racing round with each other on Christmas day