How to use Chromecast for playing music in every room of your house - CNET
Chromecast Video And Smart Displays Can Now Join Speaker Groups
How to Setup Chromecast Mult-room & Group Speakers
Amazon.com: WiiM Pro AirPlay 2 Receiver, Chromecast Audio, WiFi Multiroom Streamer, Compatible with Alexa, Siri and Google Assistant, Stream Hi-Res Audio from Spotify, Amazon Music, Tidal and More : Electronics
Google's Latest Chromecast Supports Multiroom Audio, 60fps Video - Variety