title: Filter a Content Query Web Part using the values of another web part on the same page
body: <p>I have a Content Query Web Part on my page that rolls up all the contacts lists from all the sub-webs in my site collection.  this works fine.  I'd like to be able dynamically filter the contacts rollup by having the user click on a list of leters of the aphhabet at the top of the page.  click A and see the contacts that start with A, etc...</p>
  
  <p>I'm plopping various filter web parts on the page, but don't see how to filter the results of the CQWP.  The connections menu is not much help.</p>