Is it possible to restrict category availability, so that only specific categories are available in the category metabox on the edit post screen of a specific post type?
Example: can a category of 'foo' be available on the edit screen for a specific cpt - but not the edit screen of regular posts?
(I already have a custom taxonomy for cpts, but am wondering if some but not all normal post categories can be available. This isn't purely an academic question, it has practical use.)
Either the taxonomy is common, or it is not. In other words, you may have books and movies CPTs that have an author taxonomy for their authors (lets say screen play in case of movies, to make it real). In the real world there is no much sense to say that "mark" can be an author of a book, but not a movie.
If you want to have a virtual author "hhhh" that can be associated only with books but not with movies, then it is not a real author and the best way to indicate that is to have a separate "virtual author" taxonomy.
Translating to your question.... sounds like you have categories which are not content categories, and therefor do not belong there in the first place, and should be a different taxonomy or meta data
