Mike Bibby and Eddie House are brothers-in-law who played together for the Heat in 2011.
Kareem Rush played for Indiana in 2008, with Brandon Rush on the Pacers in 2009, so they almost made it.
Brothers Jamel Thomas and Sebastian Telfair, along with cousin Stephon Marbury all played for the Celtics in the 2000's, though never at the same time.
Another weird one, Doc Rivers and Patrick Ewing played together on the Knicks, and their sons played together at Georgetown, and Georgetown played St. Johns in Madison Square Garden, the Knicks home court, against another Knicks teammate son, Anthony Mason. Also Ewing was coached by John Thompson at Georgetown, while Ewing's son played for John Thompson's son at Georgetown. Some serious connections going on there.