Mp3tag cannot do a comparison on the content of tag-fields between tracks in the listview.
Mp3tag works with the basic object, which is the one media file.
You cannot filter or compare folders, but you can filter files by their tag-field content.
Comparing folders is a task up to the user.
If you are not afraid to write an export script, then you can make this task a little more easier.
See there ...
filter for mp3’s that have more than one album name in the same folder?
There is a proposal of an export script, that creates a simple text list output of folders, which have different album names in the same folder.
You can adapt the export script to your needs.
DD.20120123.0743.CET