I have two 451r receivers for my m11x in my buggy and truggy, turn on my transmitter both cars are receiving, all good if you want to do syncrinised driving. Have two models set in the m11x run either the same problem.
Anyone know what I've dOne , got me stumped as to why

turn the car you dont want to drive off???

When you set up or select a "model", its only storing the settings that you have set. Its not like changing channels on the TV...in other words, when you select a different model, it's not like you are "changing the channel" to select a different receiver (the Futaba FHSS/S-FHSS is a slight exception). If you had 10 cars, 10 receivers and 10 models programmed into your radio (and if all the receivers have been properly bound), all 10 would do something with throttle and steering commands.

It appears that your system is functioning just fine

Dude synchronized driving would be bad ass lol! Could race your self....for amusement purposes...

Cheers for the replys fellas, first time running two receivers, just thought each Reciever would have its own signal.

Yeh have ya own ghost car lol