Jody, it is
possible to rig the two coolers up to one compressor, but, apart from being complicated, I wouldn't recommend it:
1. Your existing compressor would most likely not be big enough.
2. The plumbling to separate Tx valves is horribly complicated (keep it simple).
3. Any refrigerant leaks will take out both coolers.
If they're only a few feet apart, how about turning one into a freezer and using the other as a cooler??
Run the nearest one to your compressor as a freezer, run some 2" reinforced water hose between the bottom of the two units glassed in at either end and wrapped with as much insulation as you can fit in the space, and install an electric cooling coil up the top of the other one for auxilliary cooling.
If you put a slight gradient on the hose and get the freezer temp right, cold air will travel from the freezer to the cooler, but the cooler won't freeze because of loss from the pipe...
Crazy, I know, but it might work..