Without my intervention, the Sonos system by it self separates half of my several sonos speakers into another household (under same wifi) so the result is that through the Sonos app I can not see the speakers that were segregated into this new household.

It is the second time this happens to me in the last month, and prior occasion I had to reset all the speakers that had gone away to the system created 2nd household and repair them to my original household. 

What can be done to prevent this from happening?

What can be done to re group all speakers into one household without going through the pain of reseting?.

Thank you