If I have to guess, I’d make a wager that you have some sort of irrigation pump tied in with some soft of an indexing valve.
If I am right (and you do have a pump), you would need to install a pump relay, something like this (link)). If you don’t have a pump, pictures of the rest of your setup would be helpful.
If I am also right about the indexing valve, which looks something like this (link), than you will be able to use it with Rachio (thanks to the recent updates), but will not be able to take advantage of the flex daily schedule, which is the most economical option available.
It will be always possible to setup using your existing equipment, or convert everything to an individual zone model for most savings. Just tell us what the rest of the system looks like.