How accurate do you want your temperature? Where will you put the probe?
The problem I see is the fridge with the probe in it will be at the right temp, the other one is just being guessed at. It won't be *exactly* the same and have the same insulation/heat losses. If you can cope with one fridge being accurate, and the other fluctuating, go for it. If I was you, I'd set it up, get a pair of max/min thermometers and see what happens!
Matt