Robertson Scholars
Robertson Scholars (https://robertsonscholars.org/ ) are enrolled at both Duke and UNC and get special privileges to cross-enroll at each others schools.
Students whose primary school is UNC are still loaded into the Duke directory every semester, with an academic program type of undergraduate non-degree (you’ll see the directory show them as “U-NON”.) That status should have them load into Alma automatically from the identity management feed, and get undergraduate as a patron group.