Hard to completely understand what you're going for, but it actually sounds like a many to many relationship, not one to many. In this case, I'd have TableA which is the owner of these Grades. Then I'd have a Grade table that defines the grades. Then I'd have an OwnerGrades table that matches between the primary key of TableA and the primary key of the Grades table. Make those two columns the primary key of the third table. That way any given owner can only own one grade, but grades can be distributed to lots of owners and if you have to change the definition of a grade, it changes for everyone at the same time.

That's assuming I understand what you're asking.