Adding 'Various Artist' sub categories

Looking in my Artists list (not albums) I see 3 ‘Various’ subcategories- Christmas, Classical and Oldies.
I honestly don’t remember if I set these subcategories up or if they were done automatically by Roon.
If I did set it up, I don’t remember how I did it.
I would like to add some more ‘Various’ subcategories that will show up in my Artists list- Blues, Soundtracks, etc.
How do I do this??
Or, is there a way to add an Artist and name it ‘Blues’, and then drag/merge my blues compilation albums there??
BTW, on my portable HD (that I store my library on) the albums are sorted into these ‘Various’ subcategories. Roon does not recognize these.

I think Tags might do what you want.