<xs:simpleType name="SPLC">
  <xs:union memberTypes="KnownSPLC ValidSPLC"/>
</xs:simpleType>

<xs:simpleType name="ValidSPLC">
  <xs:annotation>
    <xs:documentation>Pattern that represents a valid 9-digit code to identify a geographic location as defined by the Standard Point Location Code product published by the National Motor Freight Traffic Association, Inc. The nesting system is State-County-City-Sub-Code, based on a nested system of recognized political entities.</xs:documentation>
    <xs:documentation>http://www.nmfta.org/pages/splc</xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
    <xs:pattern value="[0-9]{9,9}"/>
    <xs:minLength value="9"/>
    <xs:maxLength value="9"/>
  </xs:restriction>
</xs:simpleType>

<xs:simpleType name="KnownSPLC">
  <xs:annotation>
    <xs:documentation>Defines a list of known SPLCs mutually understood by the sending and receiving companies.</xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
    <!-- 
        Define your enumeration as a list of the following elements:  
        <xs:enumeration value="123456789"/> 
      -->
  </xs:restriction>
</xs:simpleType>