<p> <rs key="rGR" n="1" id="id1">XXXXX</rs>
(text text<rs key="rGR" n="2" xml:id="id3">YYYYYY</rs>, text text texts
<rs key="rGR" n="3" xml:id="id4">ZZZZZZ</rs>) text text text.
<rs key="r3" n="1" xml:id="id30">HHHHHH</rs>text text text text text.
text text <rs key="r3" n="2" xml:id="id31">KKKKKK</rs>
<rs key="r3" n="3" xml:id="id32">PPPPPPP</rs> text text text  </p>

<p> <ref id="id1">XXXXX</ref>
(text text<ptr pointer="id1">YYYYYY</ptr>, text text text
<ptr pointer="id1">ZZZZZZ</ptr>) text text text <ref id="id30">HHHHHH</rs>
text text text text text.
text text <ptr pointer="id30">KKKKKK</ptr>
<ptr pointer="id30">PPPPPPP</ptr> text text text </p>

<xsl:template match="rs[@n='1']">
<ref id="{@xml:id}"><xsl:apply-templates/></ref>
</xsl:template>