SegmentGroup 

A segment is the base element in travel, used to describe all the
different posible components of a trip In searches, Segment can be used to describe
alternative searches (such as departure from PAR or LHR, stay in single or doubles, ...
It can also be used to list segments associated to customers, agencies, destinations,
catalogues...

Element Group Information

Model

Segment | Segments
Children: Segment, Segments

Used By

Complex Types AgencyType, AirportType, CatalogueType, CityType, ContinentType, CountryType, CountyType, DistanceType, DomainType, LocationFloorType, LocationSellLocationType, LocationShopType, LocationSwimmingPoolType, LocationType, RegionType, RequesterType, SegmentCollectionType, ShipDeckType, SlopeType, StationType, StationVehicleDropOffType, StationVehiclePickupType, StationVehicleType, StopType, TransportationMeanType
Elements County, State, Terminal
Element Group ReferenceRangeGroup

Source 

<xs:group name="SegmentGroup">
  <xs:annotation>
    <xs:documentation>A segment is the base element in travel, used to describe all the different posible components of a trip In searches, Segment can be used to describe alternative searches (such as departure from PAR or LHR, stay in single or doubles, ... It can also be used to list segments associated to customers, agencies, destinations, catalogues...</xs:documentation>
  </xs:annotation>
  <xs:choice>
    <xs:annotation>
      <xs:documentation>One or many</xs:documentation>
    </xs:annotation>
    <xs:element ref="Segment"/>
    <xs:element ref="Segments"/>
  </xs:choice>
</xs:group>