Mixing 2 guitar signals

[dopey1978]

So I want to try something a bit different - I want to split my guitar signal into 2 different pedals (I'll use a y-cable for this), but then want to mix the 2 sighals back again. I'd like to make a pedal that can let me chose the ration of signals between the 2 pedals. I've attached a diagram to show what I'm trying to do.

 

Any idea how I can do this? I was thinking it should just be as simple as wiring the two input signals to a pot and wiring the output to the pot???