A festival order could contain admission, camping and parking, but each item has its own capacity and entry rules. A weekend pass does not necessarily include a campsite pitch or permission to bring a vehicle.
The system needs linked products with clear dependencies. For example, a camping extra might require a valid event pass, while parking could be limited by vehicle rather than person. Staff at different entrances need the entitlement relevant to their checkpoint.
Model a few realistic groups before development: one car with several visitors, a changed vehicle and a customer adding camping later. Test refunds affecting only part of an order. Clear confirmations should explain what has been purchased and which code is used where, reducing uncertainty at busy arrival points.
Related reading: Events Business Software Solutions.