I’m not sure if this will work, but it’s an analogous case. I have a HomePod Mini in my home office, but I prefer the sound on the Sonos One, which supports AirPlay 2.
I’ve (unimaginatively) named the Sonos speaker “One.” So my voice command is “Hey, Siri, play {name of playlist} on One,” and it does what I ask.
So if I were to try playing the audio to my MacBook Air, I expect the command would be, “Hey, Siri, play {name of playlist} on Benden.” (In the spirit of this thread, my network is Pern, the MacBook Air is Benden, the iPad is Telgar, the iPhone is Ista, and the headphones are Harper Hall.)