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.
With the limited information you have given, I would say NO. It's not an ideal approach. You should use handlers. Handlers are to a web services what filters are to a servlet. They can intercep SOAP request and response and do things with them. Is there any reason why you must use filters?