Let me explain that better…
Let’s imagine I have loads of albums spread around my library. They are filed by different artist or band names but those artists are connected in some way.
As an example, let’s take my Yes albums. There are also solo albums by Chris Squire, Jon Anderson, Alan White & Steve Howe (to name a few) dotted around my library.
In Roon there was a tagging feature. So, I could create a new tag… Let’s call it “Yes, etc.” & add all those albums to it. A bit like a playlist but less labour intensive. I would simply go to an album & select the tag I wanted to associate that album with… And it didn’t have to be a single tag, either. If I was working with classical music, I could add, say, a Beethoven album to a tag for the conductor, a separate tag for the orchestra, maybe another one for the record label (I mean, I wouldn’t because life’s too short, but I could’ve done!)
It was a really handy feature, particularly when an artist you’re into performs under a number of different names with different people. So I could create a “Vangelis, etc.” tag & add the Jon & Vangelis albums to it, but I could also add the Jon & Vangelis albums to the “Yes, etc.” tag.
So too with Neil Young, BuffaloSpringfield, Crosby Stills Nash & Young, etc.
I also added all the christmas albums by all the different artists who did them, to a christmas tag.
You get the idea.
And the “tag” button was there alongside the other icons that you see next to an album so, having created a tag, you just selected the tag(s) you wanted that album to be connected to, right there in the album.
So, aside from playlists, does Plex have anything like this, because if it doesn’t, it probably should! 
