Is there a shorter way to pull groups out of a Powershell regex?

In PowerShell I find myself doing this kind of thing over and over again for matches:

some-command | select-string '^(//[^#]*)' |
     %{some-other-command $_.matches[0].groups[1].value}

So basically - run a command that generates lines of text, and for each line I want to run a command on a regex capture inside the line (if it matches). Seems really simple. The above works, but is there a shorter way to pull out those regex capture groups? Perl had $1 and so on, if I remember right. Posh has to have something similar, right? I've seen "$matches" references on SO but can't figure out what makes that get set.

I'm very new to PowerShell btw, just started learning.