EDIT: marking as expired because one ozbargainer had a bad experience trying this.
If you buy a family ticket (2 adults 2 children) for $118, you will receive 4 tickets. However these are simply shown on the ticket as "Family of 4" rather than 2 adult tickets and 2 child tickets.
Ticketmaster let's you forward tickets to different people, a feature that helps when your group arrives separately. This allows you to split your family into 4 standalone tickets.
If you enter separately, you should be able to get in as 4 adults.
Disclaimer: I discovered this by accident when forwarding my family ticket. I have not tried this myself.
Edit: Yes this uses a backdoor to get around concession checking. If this is against the rules mods should remove.