I just have a regulator with a Y splitter and shut off valves. It's a ghetto set up, but right now I'm carbing up a British mild at 35 psi. The APA is fully carbed, so the gas is shut off to it. There's plenty to dispense, and if it goes to slow, I'll open the valve a little to get enough gas to push it. I realize if I did this long term, it wouldn't work because the second beer would eventually go flat. But for the two days or so that I'm doing it, it works just fine.
I really would like to get a second regulator, but it's just not in the budget for me. I have many other brewing equipment priorities (like a grain mill) before I buy another regulator just to have different pressures. Oh, it'd be great to have the beers carbed up according to style, but I just serve them the same and it's fine.