How to remove nodes from XML based on a conditions?

Hello Everyone

I need to remove duplicate nodes from below XML based on a condition. Can someone please help me fix the XSLT I have written? Or suggest a workaround?

My requirement: Remove entire nodes if below conditions are met.

1. If employee id has duplicate entries


2. If above condition is ‘true’, retain Worker node where in ‘Type’ is ‘Employee’. Other duplicate ‘worker’ node entry with same employee id will have ‘Type’ as ‘Contingent’.

<?xml version="1.0" encoding="UTF-8"?>
<Workers xmlns:xsi="http://ift.tt/ra1lAU">
    <Header>
        <File>22.0</File>
        <Date>2014-05-31T16:20:07.000-07:00</Date>
        <Worker_Count>2</Worker_Count>
    </Header>
    <Worker>
        <Summary>
            <Employee_ID>12345800</Employee_ID>
            <Name>John Davis (12345800)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>12345800</Employee_ID>
            <Name>John Davis (12345800)</Name>
            <Type>Contingent</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>32451854</Employee_ID>
            <Name>Felix (32451854)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>23471732</Employee_ID>
            <Name>David (23471732)</Name>
            <Type>Contingent</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>38741297</Employee_ID>
            <Name>Sam Daniel (38741297)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>38741297</Employee_ID>
            <Name>Sam Daniel (38741297)</Name>
            <Type>Contingent</Type>
        </Summary>
    </Worker>
</Workers>

Above XML need be transformed as below.

<?xml version="1.0" encoding="UTF-8"?>
<Workers xmlns:xsi="http://ift.tt/ra1lAU">
    <Header>
        <File>22.0</File>
        <Date>2014-05-31T16:20:07.000-07:00</Date>
        <Worker_Count>2</Worker_Count>
    </Header>
    <Worker>
        <Summary>
            <Employee_ID>12345800</Employee_ID>
            <Name>John Davis (12345800)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>32451854</Employee_ID>
            <Name>Felix (32451854)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>23471732</Employee_ID>
            <Name>David (23471732)</Name>
            <Type>Contingent</Type>
        </Summary>
    </Worker>
    <Worker>
        <Summary>
            <Employee_ID>38741297</Employee_ID>
            <Name>Sam Daniel (38741297)</Name>
            <Type>Employee</Type>
        </Summary>
    </Worker>
</Workers>

I have written below XSLT. Not sure how to add conditions in below XSLT to remove nodes contain duplicate employee id where in type is ‘Contingent’

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://ift.tt/tCZ8VR" xmlns:ws="urn:com.workday/workersync">
    <xsl:output method="xml" indent="yes"/>
    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
    <xsl:template match="/Workers/Worker[Summary/Type='Contingent']"/>
</xsl:stylesheet>

Above XSLT removes all Type which has value as ‘Contingent’. But, what I need is remove nodes which has Type as Contingent only when ‘Employee id’ has duplicate entries in the XML?

Request your help. Thanks Anoop