No, you'd have to plumb the return line back to tank in order to use it.
But the question is, what is your problem?
The regulator you have will hold a constant pressure at the rail so long as the pump is meeting the consumption demand. If pressure is falling off, that is a pump delivery issue (flow deficiency), and not the regulator's fault. You will find the same occurs no matter where the regulator is located.
The only effective difference is the distance any excess fuel travels back to the tank.
