First of all you need 6 people with 2 controllers, Everyone should have a Tac Insertion.

Once you have that you need 3 of the 6 people with guest signed in, in your lobby.

If its right you should have 6 total people including guests in your lobby, including you.

Now you need to press the back button and change it to Invite Only and Locale Only.

Now the other 3 people and their guest should be in lobbys by themselves.

Now you and your lobby should start searching in HCHQ.

When you do this tell the people by themselves, to press Y, Scroll over to Xbox Live
Party and highlight your gamertag and rapidly press X.

You should find a game by yourselves and the other people will join almost instantly.

Now Everybody should partner up with someone on the other Team.

You and your partner should move to a spot on the map with your guests too.

So now you and your partner and your guests should be near each other on 1 spot on the map.

Now You and Your Partner's guests will put down you Tactical Insertions and you kill your partners guest and he will kill your guest.

Now Repeat the Process.