A little FAQ:
1) how do I get in with the AZ group? - traditionally most of us sign up Bravo Co/Task Force Mullen (woodland), a few decide to go 3-color though.
2) how do I get into the AZ platoon? - To get in my platoon you get invited. A platoon has only so much space. You are always welcome to hang out in the after game activities. There is always a place for you.
3) how can I be sure I'll be with my friends? - try to sign up together and put down the same thing in the "team affilation" field, even if its not a real team.
Those seem to be the most common. Hope this helps.