How to indicate folder path for web.config default page

How might I indicate a folder path (e.g.  AppPages/PageGroup1/xyz.aspx ) In setting the default page in a web.config file, using this type of construct:

  <system.webServer>
    <defaultDocument>
      <files>
        <clear />
        <add value="xyz.aspx" />
      </files>
    </defaultDocument>
  </system.webServer>

Select allOpen in new window