The name of your group should be: "the retards" solely based on your poorly framed question.
In all seriousness though, a good name would be The Klever Klandestine Kutthroats.
The Terrific Asstastics
No, but try to think of things that you and/or your group like and connect them to charity. My friends and I, are starting a charity and we are thinking of a name that we all like.
"Harmony Duo"
Jesuits
Friends
posse comitātūs
The name for a group of ships, beginning with an "s", would be squadron.
5 fingers
sg(superb gang)..sg is my name
Arwynnatics
Either dont post them or make a group of friends and add all real friends into that group. When posting mafia wars posts, click privacy, -> customise, click friends only except from "group name". posts will be hidden from anyone in that group
A term for a group of teenagers could be a "youth squad" or a "teen clique."