4 Controllers At Different Locations Now, Wiring Relay?

My house currently has 4 controllers/stations. There is 1 controller in the garage that handles the front yard. The other 3 controllers are spread out in the backyard and the controllers are mounted to the fence outside. Each controller handles 4 zones so 16 zones total.

Is there a way to relay the backyard controllers to the garage so that I can setup the 16 zone Ranchio? For perspective, the overall plot i 1 acre so the backyard controllers are pretty far away from the garage. I do have WiFi out there but I don’t think it would be manageable to run a wire.

If not, I think I will have to buy 4 different smart controllers.