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The A/C units burn up a lot of power. I think that you'd have to upgrade your inverter, your battery system, and rewire some of the circuit breakers; before you could make this happen (if at all!
Try running the cab's A/C unit full-bore, and see if that helps. You could always hang a curtain, to separate it from the rest of the rig, and keep the cold air up front with you.
Here's what we did: