| Code | A code which links two or more Extras together, enabling a rule to be applied to all group members e.g. only one of the group may be booked, or any combination of extras may be booked.Used for an Alpha String, length exactly 1. |
| ListofExtrasRPH | A list of the RPHs of the Extras which are in this ExtraGroup. |
| RuleCode | Further clarifies how this extra is applied to a group of extras.Specifies the type of linked extras allowed : OneOf (only one of the linked extras may be booked) or AnyOf (any or all of the dependants may be booked |
| SelectionType | Describes how the extra is applied to a group of extras, e.g. "Mandatory" and "Optional."Used to indicate whether an Extra must be booked (Mandatory), may be requested (Optional) or included automatically but may be removed (Removeable). |