Is it possible to reference the previous and next elem

I am working on a navigation bar for my output HTML. 
When executing a for-each like this:
  <xsl:for-each select="//eltag[@type='subtype']">
    <xsl:sort select="@name"/>

Inside the for each I want to generate my HTML and
pass to it the previous and next element for the
navigation bar to link to:
  <xsl:apply-templates mode="createtContent"
select=".">
    <xsl:with-param name="prevEl" select="!some
expression here that references the previous element
in the for each's list!"/>
    <xsl:with-param name="nextEl" select="!some
expression here that references the next element in
the for each's list!"/>
  </xsl:apply-templates>
...

Any advice would be appricated,

IL

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