Each Doctor's office is a division of DMG and operates independently. The doctors within our group and their office phone numbers are: Stuart Felzer M.D., FACP. Premium Healthcare (302) 633-1442. Jill Mackey M.D. Mackey Family Practice (302) 660-7302. Kevin O'Hara M.D., FACP. Mill Creek Select (302) 995-2090. Current Patients..