Is it possible to use a potentiometer as a DP3T style control?
This is certainly possible, and is fairly straightforward, but not terribly simple. Let's assume your pots are in the 10k to 100k range, and you have VCAs with a 0 to 5 volt control input. Then







simulate this circuit &ndash; Schematic created using CircuitLab
will do what you want with a single pot. Note that TL081s are shown here, and will work fine, but TL084 quads will also do, and only 2 packages are needed. If you use something like this, the op amps need to be driven with +/- 9 to +/- 15 volts.