MORRISTOWN, N.J. — HFF has negotiated the sale of a 538,107-square-foot, three-building medical office complex in Morristown. The sales price was not disclosed. The three buildings are located at 435, 465 and 475 South St. and are currently 93 percent leased to Atlantic Health System. HFF represented the seller, National Business Parks Inc., in the transaction. The buyer was Harrison Street Real Estate Capital.