Halo 3 xbox live!?

We have halo 3 for xbox 360 and we have been using xbox live. we know how to make our own party, but how do you join other peoples parties? We understand that when you want ur own party u got to matchmaking, but how do u join other peoples....?


HELP! thanks :)

Halo 3 xbox live!?
You have to have them on your friends list. Then go to your friends list, go to their name, then hit 'A'and some options should show up. One of the options should be to join their party.
Reply:If the person is your friend you go to your friends list, and after you click the friends gamertag you should see a icon that says join game in progress. It should then link you into his party. Make sure that that when they are in the lobby his network says joinable, not invite only. And when your in matchmaking if you dont want people joining you, just go to where it says network and you change it to invite only. This will stop the unwanted guests! Hope i helped have a great New Years!
Reply:im srry i cant help because i have the same problem the only thing i have been able to do like that is join my friends game through an invite