PULSE_SERVER forwards the entire system audio to a remote (tcp)
network sink. A more fine-granular solution (with control on stream- instead
of system level) is almost as easy, thanks to module-tunnel-sink:
pacmd load-module module-tunnel-sink server=192.168.0.195
Now you can select the remote sink for individual streams (or turn it into the default / fallback one) and, for instance, have two different videos play back on two different remote sinks while your messenger's notification sounds remain local.