Would I just connect the coms (the middle pin on the side with three) to a pinout on the board?
P.S. If I was attempting to wire three batteries as shown in the diagram rather than two would I need another two relays? The end result here is to change three batteries from a serial wire up to parallel in order to charge them safely without any human interaction. I need the wiring to change independently using the arduino based off of a timer function.