I have an employee document type with a data type fro office departments

using checkbox list now One employee can be in multiple departments so when i save the employee in more than 1 depatment it saves the data but in xslt i cannot sort it 

here is my xslt i need to allow employees from multiple departments to be allowed to sort by parring the department name as parameter :

<xsl:variable name="DeptName" select="umbraco.library:RequestQueryString('DeptName')"/>

<div id="EmployeeMain" class="empMain">
  <xsl:for-each select="$currentPage/*[@isDoc and string(umbracoNaviHide) = '1'] ">
    <xsl:choose>  
      <xsl:when test="$DeptName != ''">  
        <xsl:if test="employeeDepartment=$DeptName">     
           <div id="empleft" class="empListMain">
          
              <div id="LeftImage" class="empImage">
                 <xsl:element name="img">
                 <xsl:attribute name="src"><xsl:value-of select="employeePicture"/></xsl:attribute>
                </xsl:element>
              </div>
     
              <div id="leftItems" class="empListText">
                <strong> <xsl:value-of select="employeeName"/></strong><br/> 
                <strong>  <xsl:value-of select="employeeDesignation"/></strong><br/>
                  Tel: <xsl:value-of select="employeePhone"/>  <br/>
                 Mobile:<xsl:value-of select="employeeMobile"/> <br/>
                 Email:<a href='mailto:{employeeEmail}'><xsl:value-of select="employeeEmail"/> </a> 
              </div>
            <br/>
            <!-- here it goes another two "new" divs -->
          </div>
        </xsl:if> 
        <xsl:if test="$DeptName='-Department-'">     
           <div id="empleft" class="empListMain">
          
              <div id="LeftImage" class="empImage">
                 <xsl:element name="img">
                 <xsl:attribute name="src"><xsl:value-of select="employeePicture"/></xsl:attribute>
                </xsl:element>
              </div>
     
              <div id="leftItems" class="empListText">
                <strong> <xsl:value-of select="employeeName"/></strong><br/> 
                <strong>  <xsl:value-of select="employeeDesignation"/></strong><br/>
                  Tel: <xsl:value-of select="employeePhone"/>  <br/>
                 Mobile:<xsl:value-of select="employeeMobile"/> <br/>
                 Email:<a href='mailto:{employeeEmail}'><xsl:value-of select="employeeEmail"/> </a> 
              </div>
            <br/>
            <!-- here it goes another two "new" divs -->
          </div>
        </xsl:if> 
     </xsl:when> 
   <xsl:otherwise>   
     <div id="empleft" class="empListMain">
       <div id="LeftImage" class="empImage">
            <xsl:element name="img">
             <xsl:attribute name="src"><xsl:value-of select="employeePicture"/></xsl:attribute>
            </xsl:element>
        </div>
        
       <div id="leftItems" class="empListText">
            <strong> <xsl:value-of select="employeeName"/></strong><br/> 
              <strong>  <xsl:value-of select="employeeDesignation"/></strong><br/>
                Tel: <xsl:value-of select="employeePhone"/>  <br/>
               Mobile:<xsl:value-of select="employeeMobile"/> <br/>
               Email:<a href='mailto:{employeeEmail}'><xsl:value-of select="employeeEmail"/> </a> 
        </div>
        <br/>
        <!-- here it goes another two "new" divs -->
      </div>
     </xsl:otherwise>
  </xsl:choose>
  </xsl:for-each>


 </div>

any code examples or suggestions wil be very useful