They all share the same +5 power source and they all share the same data line to the Arduino.
Somehow, I don't think this is going to be easy.
I'm hoping that anything I can come up with, can be used with those existing wires
I suspect that I need to find a design for a small processor controlled board that is powered by the cell being monitored and can reply to a request from a central Arduino.
Do you understand my solution?
op-amp that has a very high common mode voltage rejection rating