You should have no problems as your using Mains 60Hz AC. i.e. both supplies from the same power source.
I have managed to kill a Legacy powermaster by using two different 60Hz sources to power two different blocks. When a locomotive passed between the blocks it killed one of the powermasters. Lesson learned luckily the loco was fine.
I use a pure sine inverter so I can run my Layout on 60Hz as the U.K. mains is 50Hz. I was trying running two loops connected by switches. The two loops are electricaly isolated on the centre rail at the switches. Each loop powered by a powermaster and a powerhouse connected to a different inverter. So the sine was different on each loop.
I make sure I run both loops from the same 60Hz source now.
Nick