Common Knowledge and Multiple Authors

If a name has multiple authors, does this mean Common Knowledge for one of them or any is inaccessible? For example, three Robert Nisbets…I don't see a place for common knowledge.

There is no CK on the disamb page (because that is showing multiple authors). If you click on the specific Robert Nisbet that you want, you will be taken to his author page with his books and his CK.