Any regulator with a range of adjustment of 5-40 psi is fine. The requirement doesn't change with the number of kegs, you just get a bigger manifold. I've got a 4-way and I'm seriously thinking of moving the CO2 outside the keggerator & adding another tap.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk