The ability to cast music to a set of Assistant Speakers, Displays and clocks has been a revolution in home audio for many users. While some audiophiles still demand their quadraphonic sound systems others are happy with ubiquitous ambient audio. A key element to these systems is multi room casting and today Google just made casting to custom groups so much easier.
If you are playing music on a smart display, or a speaker group that includes a smart display, you can now customise which speakers the music is playing on in real time. To create a dynamic cast group tap on the Cast icon in the bottom left of the display. From there you can see all connected speakers, displays and Chromecast devices and can add them to a dynamic group.
For those thinking this is old news, we did first hear about this back in May but the feature never had a wide scale roll-out. Now it seems to be available to everyone.