Create a lobby (with its settings) through the GUI/overlay
...and when there's enough people, the host that created the lobby will be ejected from its SOLO game (yup the host didn't want to wait in vain and started to play alone) and go to the lobby screen where people are waiting for him to start the race.
Or maybe the host would be ejected from this game and it would just skip the lobby screen and start the race with the players that are already in the lobby waiting.