Hi Prasad,
what I understand is you are trying to do a field based split (Multi mapping in XSLT)
try this
<?xml version='1.0' ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:split="http://sap.com/xi/XI/SplitAndMerge" exclude-result-prefixes="<if any xtra NS's>">
<xsl:template match="/">
<split:Messages>
<Message1>
<a:MT_Tgt>
<xsl:for-each select="//MT_Src/ReferenceID">
<HeaderRecord>
<!-- <ur mapping>-->
</HeaderRecord>
</xsl:for-each>
</a:MT_Tgt>
</Message1>
</split:Messages>
</xsl:template>
</xsl:stylesheet>
let me know if any issues.
Thanks,
Aman Gupta