Help with merging multiple files in file1 based on identical values in file2 using VB.NET

Hi,

If file1.xml contains:

<?xml version="1.0" encoding="utf-8"?>
<Root>
  <AOP6A>
    <SN>10412</SN>
    <CHPT>104</CHPT>
    <CA></CA>
</AOP6A>
  <AOP6A>
    <SN>10471</SN>
    <CHPT>105</CHPT>
    <CA></CA>
  </AOP6A>
</Root>

and file2.xml contains:

<?xml version="1.0" encoding="utf-8"?>
<Root>
  <AOP5>
    <SN>10412</SN>
    <CHPT>104</CHPT>
    <Ctry>BEL</Ctry>
</AOP5>
  <AOP5>
    <SN>10412</SN>
    <CHPT>105</CHPT>
    <Ctry>FRA</Ctry>
  </AOP6A>

How do I enter Ctry values to iCA element in file1 based on matching SN, for example above, file1.xml should be as follows:

<?xml version="1.0" encoding="utf-8"?>
<Root>
  <AOP6A>
    <SN>10412</SN>
    <CHPT>104</CHPT>
    <CA>BEL,FRA</CA> 'Data from file2 based on SN = 10412 in both files
</AOP6A>
  <AOP6A>
    <SN>10471</SN>
    <CHPT>105</CHPT>
    <CA></CA>
  </AOP6A>
</Root>
 
Thanks,

Victor