for-each-group - only get elements in each group

Hi, I have this XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Cases>
  <Story>
    <Category>Category1</Category>
    <Case>Case1</Case>
    <Category>Category1</Category>
    <Case>Case2</Case>
    <Category>Category1</Category>
    <Case>Case3</Case>
    <Category>Category1</Category>
    <Case>Case4</Case>
    <Category>Category2</Category>
    <Case>Case5</Case>
    <Category>Category2</Category>
    <Case>Case6</Case>
    <Category>Category2</Category>
    <Case>Case7</Case>
    <Category>Category2</Category>
    <Case>Case8</Case>
  </Story>
</Cases>

I want to group on each unique <Category> element and then only include the
<Case> elements for each <Category>. Here is what I need:

<?xml version="1.0" encoding="UTF-8"?>
<cases>
   <category>Category1</category>
   <Case>Case1</Case>
   <Case>Case2</Case>
   <Case>Case3</Case>
   <Case>Case4</Case>
   <category>Category2</category>
   <Case>Case5</Case>
   <Case>Case6</Case>
   <Case>Case7</Case>
   <Case>Case8</Case>
</cases>

However, I am getting this:

<?xml version="1.0" encoding="UTF-8"?>
<cases>
   <category>Category1</category>
   <Case>Case1</Case>
   <Case>Case2</Case>
   <Case>Case3</Case>
   <Case>Case4</Case>
   <Case>Case5</Case>
   <Case>Case6</Case>
   <Case>Case7</Case>
   <Case>Case8</Case>
   <category>Category2</category>
   <Case>Case1</Case>
   <Case>Case2</Case>
   <Case>Case3</Case>
   <Case>Case4</Case>
   <Case>Case5</Case>
   <Case>Case6</Case>
   <Case>Case7</Case>
   <Case>Case8</Case>
</cases>

Here is my 2.0 stylesheet. Thanks in advance for any help. -Rick

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    exclude-result-prefixes="xs"
    version="2.0">
    
    <xsl:output method="xml" indent="yes"/>
    <xsl:strip-space elements="*"/>
    
    <xsl:template match="/">
        <cases><xsl:apply-templates select="Cases"/></cases>
    </xsl:template>
    
    <xsl:template match="Cases">
        <xsl:for-each-group select="Story" group-by="Category">
            <category><xsl:copy-of
select="current-grouping-key()"/></category>
            <xsl:apply-templates select="Case"/>
        </xsl:for-each-group>
    </xsl:template>
    
    <xsl:template match="Case">
        <Case><xsl:value-of select="."/></Case>
    </xsl:template>
    
</xsl:stylesheet>