Щас сделал вот так:
<!-- Шаблон вывода информационного элемента -->
<xsl:template match="blocks/items/item">
<xsl:param name="group_id" select="@group_id"/>
<xsl:param name="all_parent_id_1" select="//group[@id=$group_id]/@parent_id"/>
<xsl:param name="all_parent_id_2" select="//group[@id=$all_parent_id_1]/@parent_id"/>
<xsl:param name="all_parent_id_3" select="//group[@id=$all_parent_id_2]/@parent_id"/>
<!-- Название -->
<li>
<xsl:if test="$all_parent_id_1=0">
 <a href="{/document/blocks/url}{//group[@id=$group_id]/fullpath}"><xsl:value-of select="//group[@id=$group_id]/name"/></a>
</xsl:if>
<xsl:if test="$all_parent_id_1!=0 and $all_parent_id_2=0">
 <a href="{/document/blocks/url}{//group[@id=$all_parent_id_1]/fullpath}"><xsl:value-of select="//group[@id=$all_parent_id_1]/name"/></a>
</xsl:if>
<xsl:if test="$all_parent_id_2!=0 and $all_parent_id_3=0">
 <a href="{/document/blocks/url}{//group[@id=$all_parent_id_2]/fullpath}"><xsl:value-of select="//group[@id=$all_parent_id_2]/name"/></a>
</xsl:if>
<xsl:if test="$all_parent_id_3!=0">
 <a href="{/document/blocks/url}{//group[@id=$all_parent_id_3]/fullpath}"><xsl:value-of select="//group[@id=$all_parent_id_3]/name"/></a>
</xsl:if>
 / 
<a href="{item_path}"><xsl:value-of disable-output-escaping="yes" select="item_name"/></a>
</li>
</xsl:template>
Понимаю, что не совсем корректно написано, зато пока работает ))))))
Не подскажите как упростить?