PHILADELPHIA - Four members of a violent Philadelphia street group have been charged for their roles in several shootings, some fatal, that erupted in the city's Strawberry Mansion section nearly two years ago.The District Attorney's Office says the "extremely dangerous" suspects are associated with the "Big Naddy Gang" or "BNG," and are accused in five shootings that claimed the lives of two victims.Officials say they believe the shootings were used by the suspects to "boost their credibility among their contemporaries.".