Who are "The Wild Geese" in the novel, The Whites?

The “Wild Geese” is a nickname given to a former group of seven young police officers who served in the East Bronx in the 1990s. The public loved and respected the Wild Geese, who could always be counted on to ensure justice would be served. The group slowly broke up following Billy’s accidental shooting, with one member dying of cancer, another moving to Arizona, and the remaining five (Billy, Pavlicek, Yasmeen, Jimmy, and Redman) meeting up for dinner once a month and staying in regular contact with each other. With the impending demise of Pavlicek’s son, the Wild Geese decide to go back into the field as vigilantes to end the reigns of their Whites, determined that some justice should be done when no justice is available for someone like Pavlicek’s son.