XML SelectNode - Parenting

Taking this XML file

<?xml version="1.0" encoding="UTF-8"?>
<Os>
  <O>
    <name>OName1</name>
    <id>1</id>
    <tags>
    </tags>
    <Qs>
      <Q>
        <name>QName1</name>
        <id>1</id>
        <tags>
        </tags>
        <Rs>
          <R>
            <name>RName1</name>
            <id>100</id>
            <tags>
              <name>RefID</name>
              <value>72</value>
            </tags>
          </R>
          <R>
            <name>RName2</name>
            <id>121</id>
            <tags>
            </tags>
          </R>
          <R>
            <name>RName3</name>
            <id>126</id>
            <tags>
            </tags>
          </R>
		 </Rs>
		</Q>
   </Qs>
 </O>
   <O>
    <name>OName2</name>
	<id>2</id>
	</O>
</Os>	

And this PS code:

[xml]$xml1 = get-content D:\Powershell\Chunk.xml
$xml1.SelectSingleNode("//O//Q//R[id=126]")

The selectsinglenode returns

name                                                        id                                                          tags
----                                                        --                                                          ----
RName3                                                      126

I'm happy with this, what I would like now is to get the parenting nodes tree based on name or ID, such as:

Oname1 \ Qname1 \ RName3 -> based on the Name tag

or

1 \ 1 \ 126 -> based on the ID tag

Please HELP, I'm completly stuck and new with XML

TIA

Life is short, Enjoy it now. Cyreli