Prospective renters brought action against rental agency and real estate agents claiming discrimination in housing rental based on race, national origin and/or family status. On defendant's motion to dismiss, the District Court, Mordue, J., held that: (1) Extraordinary difficulty plaintiffs experienced in locating defendant despite diligent efforts afforded good cause for delay in service, and (2) plaintiffs' allegations were sufficient to state a claim against the former owner of the agency under