In the Amazon ecosystem, “Announce” is an Alexa command that sends a voice clip to every device on the local network like a PA. So you could say “Alexa, announce it’s dinner time” and every speaker would activate.
Dunno if it’s a similar framework.
You can also do this on Mac with a magic voice to all HomePods using the terminal command “sudo say -A “Time for Dinner”
Or with the voice command “intercom” as in “intercom into the living room”