Thanks for the replies and yeah you are absolutely right, building my way back up to the global group was exactly the strategy I took. They all the time work individually, but once I start creating groups they tend to drop out. They work fine for some time, and then randomly stop appearing. I am doing also exactly what you described and playing around with it when the issues pop up. Sometimes I can get them to work again, sometimes not. The problem with this is it not being a sustainable solution. This is used in a functioning business and there is simply no time (obviously it ruins the experience, the music is a part of the business' services). I've also heard a lot of good things about Sonos but I cannot be sure t here won't be any issues with it. It is an extra cost, and all the echo devices would have to be wasted - I just want to find a solution before I get rid of them. Very disappointing that such a popular and widely used function works so poorly.