They discussed multi-room audio during iOS Homekit updates and Airplay-2. The HomePod is listed as supporting Airplay-2 at bottom of page. Maybe I missed it,

They discussed multi-room audio during iOS Homekit updates and Airplay-2. The HomePod is listed as supporting Airplay-2 at bottom of page. Maybe I missed it, but there was less about multi-zone and grouping different speakers to different zones.