Two different music libraries filtering

[Sakenfor]

Edit 3: Found the best way, smart playlist, of type Album, and rule to check if path has "surround" in it.

Hi, just setup PKC, had plex for some months but new-ish to kodi, but to explain:
I have in plex, stereo music library and surround, two different folders on hard disk too.
I chose to do so as there are same albums in stereo and surround, to easily find when i want to listen
to either version. (When using plex)
So, I googled and found that there is way to advanced filter in kodi with "sources", if I understand that would split
music library by subdirectories, but with PKC sources is greyed out as nothing is added from there I think.
So, this is not directly idea, maybe as help? Or I guess it could help to bring some idea for going about splitting music library somehow in Kodi with PKC in use.

(One solution I figured for now, use PKC to add stereo music, and add manually surround folder with SMB)
(Edit 2: I guess "easiest" though most tedious would be adding suffix to surround albums)

(Hope I wrote this understandably, not native english tongue)