It would be helpful to have a role other than Parent or Grandparent that could be assigned "parental access." Some families need to have an alternative role like this for a life-partner or other non-parent guardian that should have access to a child's school information, but not be listed as "Parent" in the Directory.
There are quite a few other relationship types that you can give Parental Access to: some we use are Guardian, Consultant, Caretaker, Step-parent, etc. You have to click on Manage in the student's Contact Card to add this access.