You, and your 3 mini-posse teammates will have one week to get ALL of the new Achievements. When you all have them, your team will be "put in a hat". All teams that complete the challenge will be put in. PS3 and 360 will have separate "hats" so 8 people will be receiving prizes.
(The achievement difficulties are unknown, but once they are, the contest time may be extended or reduced to reflect the difficulty/time consumption)
Post your mini-posse in this thread and I will make a table.
Prizes are TBA