Yes, you can.  In fact, you can do almost anything you want to a single engine and leave the other alone.  If you're flying, press ALT and go to the pulldown menu labled OPTIONS and then CONTROLS then ASSIGNMENTS.  I can't remember how to do it from the startup screen (I am in a flight right now).  In the assignments go to Event Category and select Engine Commands.  This will give you a list of all the available commands for the engine systems.  Go down until you find the command you want and double-click on it.  Now you can assign either a joystick button or board key to the function by pressing the appropriate button or key.  Pay attention to what the sim tells you when you assign the function, sometimes what you input will conflict with what is already assigned somewhere else.  Just read the little blurb that comes up, and decide whether or not you want it to be that way.  Its pretty easy, but if you have any trouble I can send you some screenies of the process.

Excellent Fella's,

Both those answers seem understandable,

I need to assign the seperate engines to my strategic Commander Game Controller so I shall try Ender's answer first.

But hey if all else fails, thankyou PH_AJH for your suggestion.

Thanks again

SV2003