Grouping duplicate elements under one element

Hi,
I have the following XML fragment, and I want to group duplicate course
elements under one course element. WHat is the best way of doing it? 
Cihan


desired output is;
--------------------------
<courses>
	<course>
		<LOCAL_CRSE_CD>CTD-ECPM</LOCAL_CRSE_CD>
		<CRSE_SITE_CD>U</CRSE_SITE_CD>
		<CRSE_SITE_CD>M</CRSE_SITE_CD>
     	 	<COMP_EXTERNAL_CD>GTOP</COMP_EXTERNAL_CD>
		<COMP_EXTERNAL_CD>GTOS</COMP_EXTERNAL_CD>
	</course>
	<course>
		<LOCAL_CRSE_CD>CTD-EQD</LOCAL_CRSE_CD>
      		<CRSE_SITE_CD>U</CRSE_SITE_CD>
      		<COMP_EXTERNAL_CD>GTOT</COMP_EXTERNAL_CD>
		<COMP_EXTERNAL_CD>SVCUS</COMP_EXTERNAL_CD>
	<course>
	..
	..
<courses>
-------------

XML
---------------------
<courses>
   <course num="806">
      <LOCAL_CRSE_CD>CTD-ECPM</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>U</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>GTOS</COMP_EXTERNAL_CD>
   </course>
   <course num="2499">
      <LOCAL_CRSE_CD>CTD-ECPM</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>M</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>GTOP</COMP_EXTERNAL_CD>
   </course>
   <course num="1145">
      <LOCAL_CRSE_CD>CTD-EQD</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>U</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>GTOT</COMP_EXTERNAL_CD>
   </course>
   <course num="1146">
      <LOCAL_CRSE_CD>CTD-EQD</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>U</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>SVCUS</COMP_EXTERNAL_CD>
   </course>
   <course num="2405">
      <LOCAL_CRSE_CD>DFSSMS100</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>U</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>SO</COMP_EXTERNAL_CD>
   </course>
   <course num="2406">
      <LOCAL_CRSE_CD>DFSSMS100</LOCAL_CRSE_CD>
      <CRSE_SITE_CD>U</CRSE_SITE_CD>
      <COMP_EXTERNAL_CD>MFG</COMP_EXTERNAL_CD>
   </course>
 ....
</courses>

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