Here's a thought. You have 2 roof air conditioners, I'll assume they're ducted and are in the living area and bedroom area. Your rear a/c thermostat will keep the back cool but will shut off the compressor when it hits the set point. So set your bedroom thermostat at its lowest setting and turn off the vents in the bedroom so that all of the air is sent to the front.
On my coach I have 2 Dometic a/c's controlled by 1 thermostat in the front. There is a sensor in the bedroom that controls the rear temperature. If that is unlugged from the rear a/c then it works from the front thermostat. I added a switch so that I can turn it off when I want it to work off the front thermostat. That helps keep the front cooler on hot days.