You can combine restrictions to make complex values:

<xs:simpleType name="Status">
   <xs:restriction base="xs:integer">
      <xs:length value="2"/>
      <xs:enumeration value="23"/>
      <xs:enumeration value="29"/>
      <xs:enumeration value="31"/>
      <xs:enumeration value="37"/>
   </xs:restriction>
</xs:simpleType>