[Tanjamuse]

I have a custom column called #author_id/Author ID, which I download from fan fiction sites via FFF. The values are unique within each site; I preface them with a site identifier e.g. FF, BSV etc. The authors/Author(s) column is also downloaded from fan fiction sites via FFF.

An Author Id can use more than one Author(s) name, i.e. the ‘owner’ of an Author Id can submit stories under different pen names or simply change their pen name.

What I want is a list of books that have Author Ids that have multiple associated Author(s). So, in the attached screen shot the books from FF12345 and FF937682 would be displayed, but the book from FF45321 would not be displayed.

The number of Author Ids than have multiple pennames is small, and my library is in excess of a 100,000 books. So visually reviewing a complete list sorted on Author Id and Author is impractical.

Any ideas