Can I specify the pulseaudio "application name"?

Sometimes I play sounds from commandline with the 'play' command. This
shows up as a pulseaudio stream (aka 'sink source') named "SoX". I can
adjust the volume for that stream separate from others on my system,
no problem.

But what I'd like to do is have some set of these (eg: notification
sounds) be a different volume from others (eg: all the rest). So, I
thought maybe there's some way to specify a pulseaudio application
name other than "SoX" (maybe "SoX-my-notifications", or somesuch).
Then, I can adjust the volume for that separately, and pulse will
remember it.

But so far, I haven't found any way to do this.

Anyone know if this is possible?

I made a SO post here with some more details:
https://stackoverflow.com/questions/58277896/how-do-i-specify-the-puseaudio-application-name-when-playing-a-sound-with-sox

Thanks
-John