Yes u can, say if u were using the traxxas 4ch/5ch with switch mod controller u could use..
ch1 steering
ch2 throttle
ch3 selects 1st ESC & motor
ch4 selects 2nd ESC & motor
ch5 selects 3rd ESC & motor

this way u can run all of them at once, 2 at once, or just 1

or

ch1 steering
ch2 throttle
ch3 selects either 1st ESC & motor or 2nd ESC & motor
ch4 selects 3rd esc & motor
ch5 spare

This way u could run only 2 at once but not 1st & 2nd at the same time, only 1st & 3rd or 2nd & 3rd.

All u would do is use a electronic switch to interupt the throttle signal wire from the reciver.

There are heaps of variations of this to, there are simple on/off switches or there are switching switches that have 2 inputs/outputs.