Control water valves

Hi!

I have rachio as my garden watering system which control water valves which activates sprinklers.

I have a water valve which is far away and I don’t have that valve connected to Rachio. I automated that valve connecting a Sonoff ZBmini which goes to a 16V transformer that then connects to the valve (It needs 16V system to activate the valve).

I would like to set up an automation which turns ON the ZBmini when the rachio starts to watering and turn OFF when it stops. I am trying to simulate that the Rachio system will control the valve connected to the ZBmini.

The missing part of my project is being able to read when Rachio is activated in a specific zone. Can I do that with a Sonoff DualR3 using the S1/S2 to be able to detect when Rachio is watering? Any recommendations?

Thanks