I am working on exactly the same task. I have a solution that is running in Filemaker Server. We have purchased a Filemaker plug-in called TROI that helps us with managing XML files. It lets us list folder (to get file list of xmls in target folder), move files and delete files. We have an import script that executes the appropriate TROI functions in a LOOP that imports one file at a time. http://www.troi.com/software/fileplugin.html
This post is old so not sure if you have solved it. Let me know if this helps or not.