How to edit audiobook metadata in Books?

Since Catalina it does not seem possible to edit data for audio books in books.

Is there a way around? Has anyone found one?

I borrow audio books through an online library and often these library audio books open (in books) as separate unrelated, often unnamed, files.

This used to happen in iTunes to but there it was simple to adjusted the info, the data, so all files became 'member' of the same book and could be listened to as such.

Not so with the new books in Mac OS Catalina.

This question was asked previously in the good old year 2019, but no answer or solution seems to have been provided by Apple.

Anyone?