How to use for each group in XSL

Question

im still learning for-each-group what is the best way of grouping something like this using XSL?(by country) i'm trying to use XSL to convert this XML to another XML.

<?xml version="1.0" encoding="UTF-8"?>
<Person>
    <Student>
        <Info Country="England" Name="Dan" Age="20" Class="C" />
    </Student>
    <Student>
        <Info Country="England" Name="Dan" Age="20" Class="B" />

    </Student>
    <Student>
        <Info Country="England" Name="Sam" Age="20" Class="A" />
    </Student>

    <Student>
       <Info Country="Australia" Name="David" Age="22" Class="D" />
    </Student>
    <Student>
        <Info Country="Australia" Name="David" Age="22" Class="A" />
    </Student>

</Person>

Answer 1

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>