Using grouped HEOS speakers

Has anyone been successfully playing Spotify, or anything else, on grouped HEOS speakers?

If I group speakers in the HEOS app on iOS the HEOS app on Homey will lose contact with the speakers. I tried searching for new speakers to see if they would show up as a new speaker, but to no success.

The Homey HEOS app can’t group speakers.

As far as I understand this is possible with Sonos. The last solution would be to sell all HEOS and buy Sonos instead. But first I would like to know if someone has succeeded with this, or has any good workaround.

Nope doesn’t work here.
Error: No OAuth2 Client Found

Made an athon support ticket