Dual Tank Question

[Russell]

I asked in the engine and drivetain forum too, but I want to do this today, so I'm needing an answer

Hey all, My truck has return lines on the fuel tanks, but my tank switch is no good. I have another one, but it only has provisions for the line going to the fuel pump. Can I just put a Y-pipe into the return line setup and hook all three together? I would guess that the fuel would be more likely to run to the tank that is being drawn from due to the slight vaccum that would be made from doing the fuel drawing.

Any thoughts about this?