Split combined iTunes album into two separate albums

How does one separate two albums in one's iTunes library that have been combined into one? The albums both have the same stellar title (Greatest Hits) but are two separate albums by two separate artists. No relation whatsoever. Somehow one album was combined with the other. I've seen a lot of advice on how to combine/merge parts of an album that iTunes has split up but haven't seen any posts about dealing with the opposite problem. I've tried selecting the titles of one disc and renaming with a unique title (GH + artist's name) but this simply renames the iTunes library album that contains all of the tracks of the two (CD) albums. Is there any way to "export" or extract songs from one disc into a separate album or will I have to delete the songs from one album and try re-importing them? (It's my own CD.) Any advice most welcome!