How to use for each group in XSL
If you group by country you would start with e.g.
<xsl:template match="Person"> <xsl:for-each-group select="Student/Info" group-by="@Country"> <country name="{current-grouping-key()}"> </country> </xsl:for-each-group></xsl:template>Then you have to decide whether you want to further group the Info elements in each country group, for instance by name:
<xsl:template match="Person"> <xsl:for-each-group select="Student/Info" group-by="@Country"> <country name="{current-grouping-key()}"> <xsl:for-each-group select="current-group()" group-by="@Name"> <student name="{current-grouping-key()}"> <classes> <xsl:for-each select="current-group()"> <class><xsl:value-of select="@Class"/></class> </xsl:for-each> </classes> </student> </xsl:for-each-group> </country> </xsl:for-each-group></xsl:template>