XSLT - Create duplicate nodes from an XML

I have a multi level XML, I need to duplicate a set of nodes with a new node using XSLT 1.0 Below is a sample xml.

<?xml version="1.0"?>
<Parent>
   <ChildL1 Childtype="A">
      <ChildL1L1/>
      <ChildL1L1/>
      <ChildL1L1>
         <ChildL1L2>
      </ChildL1L1>
   </ChildL1>
   <ChildL1 Childtype="B">
      <ChildL1L1/>
      <ChildL1L1/>
      <ChildL1L1/>
   </ChildL2>
</Parent>

Desired output:

<?xml version="1.0"?>
<Parent>
   <ChildL1 Childtype="A">
      <ChildL1L1/>
      <ChildL1L1/>
      <ChildL1L1>
         <ChildL1L2>
      </ChildL1L1>
   </ChildL1>
   <ChildL1 Childtype="B">
      <ChildL1L1/>
      <ChildL1L1/>
      <ChildL1L1/>
   </ChildL2>
<NewNode>
      <ChildL1L1/>
      <ChildL1L1/>
      <ChildL1L1>
         <ChildL1L2>
      </ChildL1L1>
</NewNode>    
</Parent>

Here the NewNode has the Children nodes of ChildL1 only when Childtype="B".

Thanks in Advance; Let me know if this question is not clear. It is my first time posting this type of question.