A group will close when all members have left the group. A group will be forced to close when only one member remains. If you've stopped using your Bet With Mates group, you don't need to leave or close the group – even if the group balance is $0.00.
An Admin can also choose to close a group before any betting has started. If this happens, any members who have already joined the group will automatically have their Buy-In transferred back to their personal Sportsbet account.