How can I get devices to automatically connect to my Satellite, rather than the main router?

Does anyone know how to get my devices (on one side of my house) to automatically connect to my Satellite rather than the main router each and every time my internet disconnects/goes down for a second/after a blackout, etc?

Since the main Orbi router turns on first, they all grab onto that signal (if the power goes out, my ISP goes down, modem resets, etc) -- and stay on the MAIN routers signal (not the satellite) unless I manually go in each time and connect them on my own to the satellite....anyone know a way of doing this and making sure that devices close to the Satellite, stay on the Satellite and not the main router?

Thanks in advance!