Not really. The freezer and refrigerator are both getting cooled by the same compressor. A Johnson controller or similar turns the power on and off, without any special stuff.
I have read a few builds where folks will put a heat exchanger in the freezer and that is hooked to a pump and thermostat, in a closed loop system which cools a fermentation chamber and still keeps the freezer intact. It takes the refrigerator part out of the equation for fermentation control, and could allow you to store chilled beer in bottles or kegs in the refrigerator.