I understand your question, and I don’t have the right answer for it. But have you considered how an irrigation system works? Or you have just 4 valves and you want to turn them on.
I mean, in most irrigation systems there is a single water inlet and the zones are source from it. So to keep the pressure in control always only one zone can be active. It requires interlocking functionality to do not cause any incorrect operation. Except when you have a pump and zones, then the pump must be on and the active zone only. I hope you understand what I mean.
Otherwise there is a nice community project for ESP (wifi) based devices. ESP8266 Smart Sprinkler System
It is suddenly not fully supported in the new app, but works perfectly with the old one, and really you would probably set it up once. The rest of the work would be done by the SmartApp. (It has been recently updated and works now with the new TWC api.)