I have what looks like a filter and pressure regulator inline with the control valve for two of my zones. These are the zones that are supposed to be low pressure. But when I recently checked the pressure on the two zones, one was at 40 and the other near 60. So I think the regulators have failed (they are lik e7 years old. Replacing them in the box would be a pain for sure. But the zones surface to go to the low pressure sprinklers. So I could just put new pressure regulators there. But one of them splits in two underground. Can I put a regulator on each point where it surfaces (so total of 3). Or is there some physics that will mess up the regulation?