Okay so in a bunch of interviews and even throughout the game itself, firesquad is spoken about. Wedgwood says firesquad is a ttype of gameplay where you'll only play with your firesquad and will never be split up, also saying you'll automatically be put in a party with your squad. However. Where the f is this feature. Me and three friends try and play and we get on diff teams when we try to play online.

My reference: search
brink firesquad
On google

This info is from a post I saw the other day on here. It sounded like to create a fireteam you had to all get into the game then create the team in game, like with BC2. Don't quote me on this though as I'm still waiting for my co py to arrive.

If you have the game, check the manual at the bottom of page 21.

"Fire Teams
During online play you can press start and gain access to a team scoreboard. While on the scoreboard, you can select teammates and invite them to join a fireteam. If they accept, a private voice chat line will be automatically opened with them and you will be guaranteed to stay with them in any subsequent mission until you return to the title screen. When you are in a match with your friends, you are automatically placed into a Fireteam with them."

So it seems that the auto fire team function isn't working for you. You can try and make it yourself this way. Also other tips I have seen on the forums say to get everyone in an xbox live party and while on the first loading screen to a match invite your friends and they should be added into the same game. Whether or not they will be in your fireteam is a different story. Hope this helps.