gistfile1.xml

<mulexml:xslt-transformer name="xslt">
  <mulexml:xslt-text>
        <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
        <xsl:template match="/">
                <table>
                <xsl:for-each-group select="cities/city" group-by="@country">
                        <tr>
                        <td>
                                <xsl:value-of select="@country"/>
                        </td>
                        <td>
                                <xsl:value-of select="current-group()/@name" separator=", "/>
                        </td>
                        <td>
                                <xsl:value-of select="sum(current-group()/@pop)"/>
                        </td>
                        </tr>
                </xsl:for-each-group>
                </table>
        </xsl:template>
        </xsl:stylesheet>
  </mulexml:xslt-text>
</mulexml:xslt-transformer>