XSLT. Suppressing a node based on existence of another node

I have a source xml file as follows:

<PortfolioStatement xmlns="http://ift.tt/1sr3m0e">
<section xmlns="" name="Schedule of Investments" code="" type="Table" fundid="19" subtype="SOI" style="">
    <table xmlns:xsd="http://ift.tt/tphNwY" xmlns:xsi="http://ift.tt/ra1lAU" accountperiod="2014-10-31" style="SOI_Abbr" accountperiodtype="0" code="Abbreviation" name="Holdings" fundid="19" type="" cols="4">
        <colspec colnum="1" colname="1"/>
        <colspec colnum="2" colname="2"/>
        <colspec colnum="3" colname="3"/>
        <colspec colnum="4" colname="4"/>
        <tbody>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">      (node 1)
                <td colname="1">[~ABSYMB]ABC[#~ABSYMB]</td>
                <td colname="2">American Depositary Receipt</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">
                <td colname="1">[~ABSYMB]LP[#~ABSYMB]</td>
                <td colname="2">Limited Partnership</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">
                <td colname="1">[~ABSYMB]REIT[#~ABSYMB]</td>
                <td colname="2">Real Estate Investment Trust</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">     (node 2)
                <td colname="1">[~ABSYMB]DEF[#~ABSYMB]</td>               
                <td colname="2">Sponsored American Depositary Receipt</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
        </tbody>
    </table>
</section>
</PortfolioStatement>

What I am trying to do is suppress node 1 (as marked) if node 2 exists. Node 1 is defined as having the text 'ABC' in between the tags [~ABSYMB] and [#~ABSYMB] in its child td node. Node 2 is defined as having the text 'DEF' in between the tags [~ABSYMB] and [#~ABSYMB] in its child td node. This would leave the resultant xml looking like this:

<PortfolioStatement xmlns="http://ift.tt/1sr3m0e">
<section xmlns="" name="Schedule of Investments" code="" type="Table" fundid="19" subtype="SOI" style="">
    <table xmlns:xsd="http://ift.tt/tphNwY" xmlns:xsi="http://ift.tt/ra1lAU" accountperiod="2014-10-31" style="SOI_Abbr" accountperiodtype="0" code="Abbreviation" name="Holdings" fundid="19" type="" cols="4">
        <colspec colnum="1" colname="1"/>
        <colspec colnum="2" colname="2"/>
        <colspec colnum="3" colname="3"/>
        <colspec colnum="4" colname="4"/>
        <tbody>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">
                <td colname="1">[~ABSYMB]LP[#~ABSYMB]</td>
                <td colname="2">Limited Partnership</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">
                <td colname="1">[~ABSYMB]REIT[#~ABSYMB]</td>
                <td colname="2">Real Estate Investment Trust</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
            <tr layoutcode="" type="detail" level="2" itemtype="detail">
                <td colname="1">[~ABSYMB]DEF[#~ABSYMB]</td>
                <td colname="2">Sponsored American Depositary Receipt</td>
                <td colname="3"/>
                <td colname="4"/>
            </tr>
        </tbody>
    </table>
</section>
</PortfolioStatement>

The text vales 'ABC' and 'DEF' are setup as parameters. So far my xslt looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://ift.tt/tCZ8VR"
  xmlns:arcml="http://ift.tt/1sr3m0e"
    xmlns:fn="http://ift.tt/1fgth28"
    xmlns:xsd="http://ift.tt/tphNwY"
  xmlns:msxml="urn:schemas-microsoft-com:xslt"
  xmlns:xsi="http://ift.tt/ra1lAU"
  exclude-result-prefixes="fn msxml xsl arcml xsd xsi">

  <xsl:output indent="yes" method="xml" version="1.0" omit-xml-declaration="no"/>

   <!-- Parameters  -->

<xsl:param name="Text1">ABC</xsl:param>
<xsl:param name="Text2">DEF</xsl:param>




<!-- Identity template -->
  <xsl:template match="node()|@*">
    <xsl:copy>
      <xsl:apply-templates select="node()|@*"/>
    </xsl:copy>
  </xsl:template>


<xsl:template match="tr[td]">
    <xsl:choose>

        <xsl:when test="substring-before(substring-after(.,'[~ABSYMB]'),'[#~ABSYMB]')=$Text1">

        </xsl:when>
        <xsl:otherwise>
            <xsl:copy>
                <xsl:apply-templates select="node()|@*"/>
            </xsl:copy>
        </xsl:otherwise>
    </xsl:choose>
</xsl:template>

</xsl:stylesheet>

This locates node1 but I don't know how to check for the existence of node2 to perform the match pattern override.

I get the feeling it is probably more confusing to describe my problem than it is to solve it and for that I apologise. Many thanks in advance for any advice anyone has.