I read all these news stories about adding the shield TV to a speaker group. I've updated Chromecast built-in to the beta version. But I never see the option on the app.
With the gradual rollout or US only? Or is it something that appeared and disappeared?
It work for MiBox too but only for several days. I managed to get working but after two days, i made a restart on one device and lost the ability to work on group speakers. I think it was a mistake made by Google developers and that function is not intended to ve relesed.