Rear Wheel RC Steering?

Ok, so before I actually get to my question let me explain what I am doing.

I have a traxxas rustler, I wan't to put 4 wheel steering on it, and I wan't it to be very stable.  I know how I am going to set up the steering, but I need help with the electronics of it.  The stock reciever has a channel 1 output (to ESC) two channel 2's (for two servos) a channel three, and a channel 4. 
I wan't this car to be able to switch one of the servo's from inverted to not inverted using channel three which is the output of a two position switch.  Is there a way to do this without mechanically connecting the whole fancy layout seen below?

Picture of Rear Wheel RC Steering?
Re-design5 years ago
Unless you are willing to do something "mechanical" on the receiver end the only way to do what you want is to change to a computer transmitter. Using a computer transmitter you can assign servo direction and switch assignment using a menu. (author)  Re-design5 years ago
I have looked into the computer transmitters, but what I have found is that you can only output one channel from one control (I couldn't just run the car like normal and make the steering wheel also on channel three). I may be mistaken though, can you output channel 2 and 3 from one control on the remote, then use a switch to invert channel 3.
With the right transmitter you can. I didn't do cars though, I did R/C airplanes. With my transmitter you could reprogram several switches/controls etc. to which ever servo/direction/speed etc. Lots of airplanes have 8-10 servos or more and you can create very complicated setups with them. (author)  Re-design5 years ago
Ok, thanks, those remotes are expensive enough I will just stick to my mechanical plan though probably. Or, I could get a plane controller and use the two sticks to control the front and rear wheels for fully custom steering combinations.