tests/resources/group/group.xsd

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="attr_group_simple" elementFormDefault="qualified">
  <xs:include schemaLocation="address.xsd" />
  <xs:group name="address2" ref="address1">
    <xs:sequence>
      <xs:element name="road" type="xs:string"/>
    </xs:sequence>
  </xs:group>
  <xs:element name="Student">
    <xs:complexType>
      <xs:group ref="address2"/>
    </xs:complexType>
  </xs:element>
</xs:schema>