This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
XML parsers don't do content filtering. That's something you would have to do after the parsing is finished. If you were using a SAX or StAX parser instead of DOM, this kind of thing would be easier to implement because you have more control over the parsing process.