I have a strange problem here.... I have a uboat with 2 engines, I need to be able to control them in unison or independantly ( i.e. one in full forward and one in full reverse or any mixture in between)

I am assuming that I need 2 channels and 2 speed controllers, butI don't see any transmitters set up for dual engine control ( Seems to me like I need 3 joysticks!)

Has anyone done this before?
Any suggestions?
Help!

-sean