Formatting Genre String

[simbun]

It might be quicker to test it yourself by copying an existing album, modifying its album name and inserting the relevant multi-value seperator before loading it back into iTunes to see how it handles it.

If you're on Windows the easiest way would be to install mp3tag.
With a default installation, once you've dragged your copied files onto the UI it'll identify the tagging format for you (ID3v2.3 or ID3v2.4 hopefully) in the Tag column.

If it states it's ID3v2.3:
mp3tag doesn't write a per-spec ID3v2.3 tag so it's best to test with the official separator and with mp3Tags separator (which translates it into a NULL) by typing 'Artist1/Artist2' into the Artist tag, and 'Genre1\\Genre2' into the genre tag, before saving your changes.

If it states it's ID3v2.4 (which uses a NULL separator):
Just type 'Genre1\\Genre2' in the genre tag.

If it states it's anything other than just 'ID3v2.3' or 'ID3v2.4' let us know.

Load the modified album into iTunes, and let us know if the modified tags appear any different to the strings you entered in mp3tag.


EDIT: I've just noticed that mp3tag doesn't save in the same format as the incoming, so best to go to Tools > Options > Tags > Mpeg, and in the 'Write' panel, disable ID3v1, and select ID3v2.4 if the incoming files are 2.4, or ID3v2.3 UTF-16 if the incoming files are ID3v2.3. This assumes the incoming files have just one format (as mentioned above, let us know if there are more than one).