Hi David (and welcome aboard ausmicro.com!)
Unfortunately the answer is “NO”. Vehicles on EXACTLY the same frequency cannot race unless they use something like FM PCM digital signatures on their respective TX/RX units. Of course, Bit Char-G cars have simple AM TX/RX units so – any cars on the same frequency set will mean conflict.
Even cars on the same band but slightly different frequencies (eg 45MHz standard or spec edand45MHz booster car) tend to conflict in some units due to the loose frequency tolerance offered by the cars and controllers.
Cheers
Derek