In an interview with IGN, Rockstar has revealed details regarding their crew system in multiplayer which is essentially the same as forming clans.
Crews that are formed playing Max Payne 3‘s multiplayer will be able to be used for future Rockstar games, including Grand Theft Auto 5. There will be private and public crews that are both customizable formed through the integration of Social Club which allows stats to be tracked.
Rockstar is introducing a feature called “Vendettas” in Max Payne 3′s multiplayer which is to add intrigue, if someone kills you twice; you can initiate a vendetta against the player and your map will have an X to mark the player’s spot, kill them and you get bonus XP.
Crews will have feuds, which is basically the same with vendettas but is more random. Spot two or more members of a crew and a feud will begin. A skirmish will be initiated and whichever crew reaches 10 kills first will be crowned the victor.