hi clay,
 you could write in your xsl, a call of the  other xml file  by the document()
function.


<xsl:for-each select="document('c:\temp\sourcexml2.xml')">
     <xsl:for-each select="//CUSTOMER[@id= $CustID]">
          <h2>
               <xsl:value-of select="FIRSTNAME"/>
          </h2>
     </xsl:for-each>
<xsl:for-each>

maybe it helps.

thomas



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