ModNation Racers

Unobtainable due to server closure

From the ModSpot, drive over to the Race Station and then drive to the Online booth and click . Choose 'Host Casual', choose a track and then set privacy to 'Private'. In the lobby, click and then click on the friend you want to invite. Chose 'Invites/Messages' and then 'Invite to Gameroom'. You have to repeat that last step on four more different friends and this trophy will unlock. You only need to invite friends, you don't need to actually race.

I personally had problems getting this trophy to unlock. I therefore went on to challenge random people in the ModSpot. Just drive over to anyone, click , choose 'Challenge' and then set up the race. Repeat this four more times and it should unlock. The one you challenge doesn't need to answer for it to work.