I need help.....

For once, I need help. If anyone that reads this post and has an Xbox 360 and has Halo 3: ODST and is willing to help me get the firefight achievement, send me a message. If you do want to help, send a message to hemmett14 on LIVE. No caps or spaces. Thanks. Oh! Also, remember, there has to be four people to do the acheivement.