adding attribute to the node

Question

I am trying to add an attribute to the node if the child node value is equal to some string.

I have a main.xml file

<Employees>    
 <Employee>     
 <countryid>32</countryid>
 <id name="id">1</id>
 <firstname >ABC</firstname>
 <lastname >XYZ</lastname>     
 </Employee>
 <Employee>     
 <countryid>100</countryid>
 <id name="id">2</id>
 <firstname >ddd</firstname>
 <lastname >ggg</lastname>     
 </Employee>
 </Employees>    

So let's say if the country id is equal to 32 then it should add attribute country=32 to Employee node. The output should be like below :

output.xml

 <Employees>    
 <Employee countryid="32">     
 <countryid>32</countryid>
 <id name="id">1</id>
 <firstname >ABC</firstname>
 <lastname >XYZ</lastname>     
 </Employee>
 <Employee>     
 <countryid>100</countryid>
 <id name="id">2</id>
 <firstname >ddd</firstname>
 <lastname >ggg</lastname>     
 </Employee>
 </Employees>    

I am using the following script but getting error that An attribute node cannot be create after the children of containing element.:

Transform.xsl

<xsl:template match="/">        
    <xsl:apply-templates />
</xsl:template>

<xsl:template match="Employees/Employee/countryid[.=32']">
  <xsl:attribute name="countryid">32</xsl:attribute>
  <xsl:copy>
    <xsl:apply-templates select="@* | node()"/>
  </xsl:copy>
</xsl:template>

Any help will be appreciated. Also can we pass countryid as comma seprated values so that i can pass 32,100 and then it should add attribute to all the matching nodes.

Thanks.