I have an xml document that essentially encapsulates records in a dataset.
It contains data for columns, and records and fields within records.
Using my xsl, I am able to output a table style format of the data in html.
I now want to be able to group by a value in one of the fields. I have
included the xml example and xsl below.

Currently my view looks like this:

Name  Test   Result   Result Group   Normal Range   Range Indicator  Units
Test Site  Date
Name  Test   Result   Result Group   Normal Range   Range Indicator  Units
Test Site  Date

What I want is

Date
Name  Test   Result   Result Group   Normal Range   Range Indicator  Units
Test Site
Name  Test   Result   Result Group   Normal Range   Range Indicator  Units
Test Site

Date
Name  Test   Result   Result Group   Normal Range   Range Indicator  Units
Test Site

The solution is escaping me, as I haven't quite grasped xsl yet.  Any help
would be appreciated.

my xsl and xml are below:

Here is an example of my xsl:
<?xml version='1.0'?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html"/>

<xsl:template match="ProviderData/Ts/T[1]">
 <style>
  TD.Label
  {
   background-color:#E0E0E0;
   border-color:LightSteelBlue;
   border-width:1px;
   border-style:solid;
   font-family:Arial;
  }
  TD.Field
  {
   border-color:LightSteelBlue;
   border-width:1px;
   border-style:solid;
   font-family:Arial;
   COLOR: black
  }
 </style>
 <table width="98%"><tr><td class="Label"><b><span style="font-size:15">Lab
Results</span></b></td></tr></table>
 <table cellpadding="1" width="98%">
  <tr>
   <td class="Label" width="200"><xsl:value-of
select="Cs/C[1]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[2]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[3]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[4]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[5]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[6]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[7]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[8]/@N"></xsl:value-of></td>
   <td class="Label" width="60"><xsl:value-of
select="Cs/C[9]/@N"></xsl:value-of></td>
  </tr>
        <xsl:for-each select="Rs/R">
            <tr>
    <xsl:attribute name="style">background-color:
    <xsl:if test="position() mod 2 = 1">#EEEEEE</xsl:if>
    <xsl:if test="position() mod 2 = 0">Gainsboro</xsl:if>
    </xsl:attribute>
    <xsl:for-each select="Fs/F">
                 <td>
                  <xsl:value-of select="@V"/>
                 </td>
                </xsl:for-each>
            </tr>
        </xsl:for-each>
      </table>
 </xsl:template>
</xsl:stylesheet>

Here is an example of my xml:
<?xml version="1.0" encoding="Windows-1252" ?>
  <!DOCTYPE ProviderResults (View Source for full doctype...)>
  <ProviderData>
   <Ts>
    <T N="Table">
     <Cs>
      <C I="0" N="Name" />
     <C I="1" N="Test" />
      <C I="2" N="Result" />
      <C I="3" N="Result Group" />
      <C I="4" N="Normal Range" />
      <C I="5" N="Range Indicator" />
      <C I="6" N="Units" />
      <C I="7" N="Test Site" />
    <C I="8" N="Date" />
     </Cs>
     <Rs>
      <R I="0">
       <Fs>
        <F I="0" V="Albumin" />
        <F I="1" V="555.1620" />
        <F I="2" V="39" />
       <F I="3" V="A" />
        <F I="4" V="33-53" />
        <F I="5" V="" />
        <F I="6" V="g/L" />
        <F I="7" V="ML" />
      <F I="8" V="01/01/2004" />
      </Fs>
      </R>
      <R I="1">
       <Fs>
        <F I="0" V="Alkaline Phophatase" />
        <F I="1" V="111.1850" />
        <F I="2" V="119" />
        <F I="3" V="A" />
        <F I="4" V="43-122" />
        <F I="5" V="" />
        <F I="6" V="U/L" />
        <F I="7" V="ML" />
      <F I="8" V="01/01/2004" />
       </Fs>
      </R>
    <R I="1">
       <Fs>
        <F I="0" V="Alkaline Phophatase" />
        <F I="1" V="000.1800" />
        <F I="2" V="119" />
        <F I="3" V="B" />
        <F I="4" V="43-122" />
        <F I="5" V="" />
        <F I="6" V="U/L" />
        <F I="7" V="ML" />
      <F I="8" V="01/01/2005" />
       </Fs>
      </R>
     </Rs>
    </T>
   </Ts>
  </ProviderData>