Three West Marin groups—West Marin Community Services, West Marin Senior Services and the San Geronimo Valley Community Center—were among 15 recipients of a $5 million, two-year grant from the Marin Community Foundation to shore up safety-net social services. “It’s a network [of groups] that goes largely unheralded,” said Tom Peters, the foundation’s president and C.E.O. “But you sure would know it if they weren’t able to provide these basic services.” The grants represent slight increases…