The panel in charge of selling Prince George's County's ailing hospital system is warning Maryland leaders that the economic climate might make finding one buyer impossible and is asking permission to sell the health facilities piecemeal. At its monthly meeting, the Prince George's Hospital Authority agreed to ask the Maryland General Assembly to allow the authority to sell the county-owned system's three hospitals and two nursing homes separately. That could mean different buyers for the more stable hospitals in Bowie and Laurel than for the system's flagship, Cheverly-based Prince George's Hospital Center.