Wow that is really cool. Thanks! (And thank everyone else too!) Your update about doing db updates at same time as filtering is also pertinent.

Yes I will have to study the module to see how to specify rules for subtrees nested inside the Company tag. My description wasn't so great. My data is basically a Feed of many Company twigs each wrapped in an Entity.

<Feed>
 <Entity>
  <Company>
   <Identity>
    <Address>...
   </Identity>
   <Executives>
     <Section>
       <Executive>
       <Executive>
     </Section>
  ...
  </Company>
 </Entity>
 <Entity>
   <Company>
...
[download]

and so on.