(N.B.: Below, AA=AlbumArtist)
Yes, you can edit AAsort in MusicBee:
* Open the tag editor (right click -> Edit)
* Select 'Sorting' tab
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There is a SECOND OPTION.
If you are satisfied with all the values in AAsort and do not wish to maintain both tags (AA and AAsort), you can copy AAsort into AA (with mp3tag) and then forget about AAsort.
Moreover, AA is always easily accessible in MB's interface (more easily than AAsort).
But make sure that AA is always in the desired format: "SURNAME, given names".
In a first phase, especially for newbies who are afraid of making mistakes when converting tags with mp3tags, it's good to have both tags (AA + AAsort), so that you can always correct/tweak your conversion formulas, while keeping the original values.
And afterwards? The choice is yours.