I have multiple Sonos connect amps. All are Ethernet connected to my Eero routers. There are 4 Eero routers all on the same network and there are no wifi issues. Two of the amps do not show up on the app and often show up together but without the others. Right now on one iPhone I see 7 amps and on another iPhone I see 2. Sometime one or two others also go to a different network. The iPhones are on the same wifi network. Any suggestions how to get them all together? Update--i went on the Sonos web app and I see that I hace 4 systems.  i just want one system so that i can access all of my amps from a single phone.