You should be fine. Rachio can run up to 3 valves at a time. It looks like you have a master valve in your system, so that would limit you to 2 zones tied together, making the MV the third.
I currently have 3 zones in each of my 3 front yard sections tied together when I switched from pop up spray nozzles to MP-Rotator nozzles. It was supposed to be temporary until I had time to dig up and re-pipe my zones, but here we are 3 years later, still wired together… 