creating multiple xml documents from one large xml do

I'm working with salesforce soap xml, 3 namespaces, I am splitting them
currently with python. I need a simpler way and hoping I can do it with XML.

Each case has this as the beginning node and element of course with the end
tag, for each case I want everything in between in each file.
If there is no case node skip

<records xsi:type="sf:CaseNote_GCC__c">
Insert child node with date it was created

There are 2 child nodes I want to name the file with
<sf:Id>xxxxxxxxxxxxxx</sf:Id> and <sf:CaseNumber>xxxxxxxxxxx</sf:CaseNumber>

Thanks for your help.

Phil Legault