If this is data that iTunes only holds in its database and only for files that have been acquired via iTunes and it is no data that is stored in tag fields or read by iTunes from tag fields - hard luck.
See also here:
If this data is only available on album level then I doubt that this can be editted by MP3tag as MP3tag does no know anything about albums. The data has to be stored in each file, there is no place to put data that is only visible for the album - this would be something that only the player can supply.