You could utilize the server/client functionality over the local network instead of using the same process.

So you could point the other users to the machine's local address and they would automatically find the Pipewire server. Maybe? I guess? It's just a theory.

https://wiki.archlinux.org/title/PipeWire#Sharing_audio_devices_with_computers_on_the_network

This thread seems to have what you're looking for.

https://bbs.archlinux.org/viewtopic.php?id=265878

According to the thread, its possible to provide system-wide usage by enabling this option at build time:

-Dsystemd-system-service=enabled

Or it seems like you could share it over the local network by editing the Pipewire config file and making an environment variable. (See post #5.)

Or you could

Just add the "player" user to the "audio" group

according to post #8.

Note: it seems like Pipewire runs on port 4713. So the server would run on 0.0.0.0:4713, I guess.