If I understand your problem correctly, you are using the same action class for all of your events, but you are returning a different result for each event and using the struts.xml file to control which directory's JSP the application uses to display the data. If this is correct, then you maybe be able to solve your problem by having a single result that your action class uses any time it completes successfully. This result will go to a JSP that has a jsp:include tag in it that gives control to the correct JSP. I've never put anything dynamic in the "page" attribute of a jsp:include, so I'm not exaclty sure what your options are. I doubt you can use s:property tag, EL might work, if all that fails, you could write a scriptlet (shame on me for saying that).
Alternatively, I you want to automatically update the struts.xml file, I think you can reload it with:
I've never done this, but if that works better for you, you might want to give it a try.