Allow for group rate packages. For example, at a homeschool conference, a family may register all together at a certain fixed price point. At that price, they get two adult attendees (parents), unlimited (or limited) kids, and a certain amount of guests. All at one fixed price. Certain ticket types should be able to be limited to a package as well. Internal Ref: https://app.clubhouse.io/event1/story/575/registration-packages