I read that it's probably a "favorites vs. family" - a tribe of returning players who compete against a tribe of loved ones of each of the returnees.
I might guess you compete against your loved one, but then after a merge... Is blood thicker than water? (I would say yes - if I can't win the million, I want Dad/Sis/Uncle to, even if he/she was on the other tribe!)
So, basically, more recycling of players...
Aras Baskauskas (winner in Panama), RC Saint-Amour (oh,no - that laugh), Kat Edorsson (hehe), Stephanie Valencia (Russell Hantz's girl alliance), Rob Cesternino and Tina Wesson (3rd try), Gervase Peterson (also hehe), Terry Deitz, Natalie Bolton, and evil wacko Colton Cumbie.