An XML file for inclusion:

<page xmlns="http://projectmallard.org/1.0/"
      xmlns:its="http://www.w3.org/2005/11/its">

  <info>
    <revision pkgversion="3.8" date="2013-04-19" status="candidate"/>

    <credit type="author copyright editor">
      <name>Rupert Monkey</name>
      <email its:translate="no">rupert@example.com</email>
      <years>2013</years>
    </credit>

    <include href="legal.xml" xmlns="http://www.w3.org/2001/XInclude"/>

  </info>

  <comment>
    <cite href="mailto:rupert@example.com">Rupert Monkey</cite>
    <p>This snippet is included on other pages.</p>
  </comment>

  <steps>
    <item>
      <p>Some item for inclusion</item>
    </item>
  </steps>

</page>

Include the steps in another file:

  <include href="some-item.xml"
    xpointer="xmlns(mal=http://projectmallard.org/1.0/)xpointer(/mal:page/mal:steps)"
    xmlns="http://www.w3.org/2001/XInclude"/>