<xs:group name="BookingTransactions">
    <xs:choice>
        <xs:element ref="AdQuotationRequest" maxOccurs="unbounded" />
        <xs:element ref="AdQuotation" maxOccurs="unbounded" />
        <xs:element ref="AdQuotationStatusEnquiry" maxOccurs="unbounded" />
        <xs:element ref="AdQuotationStatus" maxOccurs="unbounded" />
        <xs:element ref="AdReservation" maxOccurs="unbounded" />
        <xs:element ref="AdReservationChange" maxOccurs="unbounded" />
        <xs:element ref="AdReservationCancellation" maxOccurs="unbounded" />
        <xs:element ref="AdReservationResponse" maxOccurs="unbounded" />
        <xs:element ref="AdReservationStatusEnquiry" maxOccurs="unbounded" />
        <xs:element ref="AdReservationStatus" maxOccurs="unbounded" />
        <xs:element ref="AdOrder" maxOccurs="unbounded" />
        <xs:element ref="AdOrderChange" maxOccurs="unbounded" />
        <xs:element ref="AdOrderResponse" maxOccurs="unbounded" />
        <xs:element ref="AdOrderCancellation" maxOccurs="unbounded" />
        <xs:element ref="AdOrderStatusEnquiry" maxOccurs="unbounded" />
        <xs:element ref="AdOrderStatus" maxOccurs="unbounded" />
        <xs:element ref="adsml:AdministrativeResponse" />
    </xs:choice>
</xs:group>