Adrien, for the PE solution, you just run the right/left speaker wires from "the amp" to the distribution panel. Then, you run R/L from the distribution panel to each volume control. I used 16/4 wire even though it's a fairly long run and it worked just fine. Then you run the right and left from the volume knob to each speaker.
It's designed for stereo pairs; I don't think it would work to have two pairs on one volume knob.
The panel I linked to is good for four pairs. I think there might be panels that accommodate more, though.
