<element name="base"
xmlns="http://relaxng.org/ns/structure/1.0">
  <choice>
    <group>
      <element name="data"> 
        <value>firstValue</value>
      </element>
      <oneOrMore>
        <element name="option">
          <element name="value">
            <text/>
          </element>
          <element name="label">
            <text/>
          </element>
        </element>
      </oneOrMore>
    </group>
    <group>
      <element name="data"> 
        <value>secondValue</value>
      </element>
      <oneOrMore>
        <element name="option">
          <element name="value">
            <text/>
          </element>
          <element name="label">
            <text/>
          </element>
        </element>
      </oneOrMore>            
    </group>
  </choice>
</element>