The time I wish for this feature is when I have to trim my reference list because of space constraints placed upon me by publications!
My workaround the last time, was to unformat the citations to temporary, - temporarily delete those records I didn’t want from library, reformat the papers and when each of those citations came I skipped, so I could go back and search for temp refs and delete the ones I didn’t want. Reformated the paper, and then remembered to return the deleted records to my library from trash!.