any string that follow after the string "c d" and is followed by the
string "g h"

If pattern found:
Surround with<found-you>

<xsl:analyze-string select="$something" regex="(e f *)(g h)">
 <xsl-matching-substring>
   <xsl:value-of select="regex-group(1)"/>
   <found-you>
   <xsl:value-of select="regex-group(2)"/>
    </found-you>
  </xsl:matching-substring>
   <xsl:non-matching-substring>
   <xsl:value-of select="."/>

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