You could also sort by a property like path and then press Ctrl-G to select a group of files with the same contents as the first selected file.
The discussion about several instances of MP3tag has be held a couple of times and nothing has changed in the meantime.
see e.g. this one from 2014:
But so was the discussion about font selection - and now it is possible.
So, until the feature is implemented, I would suggest that you either adapt your workflow so that it uses already existing functions or live with the way you currently chose.