Where do DJ's like DJ Diamond Kuts and DJ Damage, get all their Philly/Jersey/Baltimore Club Party Music?

On the radio stations in Philadelphia - Power 99 and 100.3 The Beat, Diamond Kuts and Damage are two of the most popular DJ's for spinning Party Club music on the radio. Where on earth do they get all their club party music? Does someone specifically make it for them? Some of it is really awesome, and I would love to get my hands on it.