Or you select the files, see that ARTIST switches to "
<keep>" which means that there is more than 1 name so you enter "Various" in ALBUMARTIST and save the modification.
I still have problems with the general approach: there are so many collaborations of artists where more than just the ALBUMARTIST appears as ARTIST - but this still would not qualify to be called a compilation with "Various Artists". It is just an album, issued by one artist who features some of his colleagues.
So you have to check each album anyway. And then the manual way would be the fastest as you do not have to export/import data.