User blog comment:AndreEagle17/Breaking News, GTA VI is confirmed!/@comment-4995321-20150207172856/@comment-25073525-20150207181706

"Ability to switch between Niko Bellic, Jimmy Hopkins, Franklin Clinton, Michael De Santa, Trevor Philips, Devin Weston, and Carl Johnson"

Cononically if you keep both Trevor and Michael alive then you have to kill Devin Weston.

And by the way it will take Rockstar a lot of time to put all those cities in same game. Why don't you wish the game to be set on Mars?;)