Books in a bundle

[Matthias]

This topic is about this book:
https://www.goodreads.com/book/show/1...
ISBN: 9783608939996

This is the german edition of "The Lord Of The Rings" trilogy.
It is a bundle of 3 (physical) books sold together with the same ISBN.

The linked book-entry lists it as (The Lord of the Rings #1) and displays it as edition of "The Fellowship Of The Ring".
While "The Fellowship…" is contained in this bundle, there are also "Return of the King" and "The two towers" in the same bundle.

What is the correct way to proceed here?
Is this entry misattributed to "Lord of the Rings #1"/"The Fellowship…" or should it be split into three entries with the same ISBN?

[vicki_girl]

If the set only has one ISBN, then it should be separated from "The fellowship..." and combined with the omnibus editions:

https://www.goodreads.com/book/show/3...

[Renske]

Done and edited ISBN