XSL issue

I have an XSL file that transforms the same data from one XML format to another. I am having trouble with one aspect of it though... If two of the <Attributes ID=""></Attributes>  nodes have the same ID value then I need to present them as one Node in the new format. Pay particular attential to the nodes where id=14.

The logic is that in the old format, if the <Value> node has an id of -6 then there may be a corresponding <Attributes> node (with the same ID value) that contains a <ValueLiteral>  node with a string that, in the new version needs to be placed in the same <Attributes> node instead of having two <Attributes> nodes with the same ID.

Any help Getting this XSL working properly will be greatly appreciated.

Here is my XSL:

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<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" >
<xsl:template match="/">
<Attributes>
<xsl:for-each select="//AttributeSet" >
<AttributeSet>
<xsl:attribute name="id">
<xsl:value-of select="@id" />
</xsl:attribute>
<xsl:for-each select="Attribute" >
<Attribute>
<xsl:attribute name="id">
<xsl:value-of select="@id" />
</xsl:attribute>
<ValueList>
<xsl:for-each select="Value" >
<Value>
<xsl:choose>
<xsl:when test="@id">
<xsl:attribute name="id">
<xsl:value-of select="@id" />
</xsl:attribute>
</xsl:when>
<xsl:otherwise>
<ValueLiteral>
<xsl:value-of select="Name" />
</ValueLiteral>
</xsl:otherwise>
</xsl:choose>
</Value>

</xsl:for-each>
</ValueList>
</Attribute>
</xsl:for-each>
</AttributeSet>
</xsl:for-each>
</Attributes>
</xsl:template>
</xsl:stylesheet>



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Here is my original XML that I need to apply the XSL to:

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<?xml version="1.0" encoding="UTF-8" ?>
<SelectedAttributes>
      <AttributeSet id="1951">
            <Attribute id="6">
                  <Value id="31246" />
            </Attribute>
            <Attribute id="31245">
                  <Value id="31253" />
            </Attribute>
            <Attribute id="26446">
                  <Value>
                        <Name>13</Name>
                  </Value>
            </Attribute>
            <Attribute id="14">
                  <Value id="-6" />
            </Attribute>
            <Attribute id="14">
                  <Value>
                        <Name>BRAND NAME</Name>
                  </Value>
            </Attribute>
            <Attribute id="31243">
                  <Value id="31279" />
            </Attribute>
            <Attribute id="10244">
                  <Value id="-10" />
            </Attribute>
      </AttributeSet>
</SelectedAttributes>

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Here is the output I am currently getting:
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<?xml version="1.0" encoding="UTF-8"?>
<Attributes>
      <AttributeSet id="1951">
            <Attribute id="6">
                  <ValueList>
                        <Value id="31246"/>
                  </ValueList>
            </Attribute>
            <Attribute id="31245">
                  <ValueList>
                        <Value id="31253"/>
                  </ValueList>
            </Attribute>
            <Attribute id="26446">
                  <ValueList>
                        <Value>
                              <ValueLiteral>13</ValueLiteral>
                        </Value>
                  </ValueList>
            </Attribute>
            <Attribute id="14">
                  <ValueList>
                        <Value id="-6"/>
                  </ValueList>
            </Attribute>
            <Attribute id="14">
                  <ValueList>
                        <Value>
                              <ValueLiteral>BRAND NAME</ValueLiteral>
                        </Value>
                  </ValueList>
            </Attribute>
            <Attribute id="31243">
                  <ValueList>
                        <Value id="31279"/>
                  </ValueList>
            </Attribute>
            <Attribute id="10244">
                  <ValueList>
                        <Value id="-10"/>
                  </ValueList>
            </Attribute>
      </AttributeSet>
</Attributes>
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Here is the output I want:
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<?xml version="1.0" encoding="UTF-8" ?>
<Attributes>
      <AttributeSet id="1951" categoryId="50604">
            <Attribute id="31245">
                  <ValueList>
                        <Value id="31253" />
                  </ValueList>
            </Attribute>
            <Attribute id="31243">
                  <ValueList>
                        <Value id="31279" />
                  </ValueList>
              </Attribute>
            <Attribute id="10244">
                  <ValueList>
                        <Value id="-10" />
                  </ValueList>
            </Attribute>
            <Attribute id="6">
                  <ValueList>
                        <Value id="31246" />
                  </ValueList>
            </Attribute>
            <Attribute id="26446">
                  <ValueList>
                        <Value id="-3">
                              <ValueLiteral>13</ValueLiteral>
                        </Value>
                  </ValueList>
            </Attribute>
            <Attribute id="14">
                  <ValueList>
                        <Value id="-6">
                              <ValueLiteral>BRAND NAME</ValueLiteral>
                        </Value>
                  </ValueList>
            </Attribute>
      </AttributeSet>
</Attributes>