Thank you for the quick reply and confirmation of the behavior I was seeing.
In case someone else runs into the issue of needing different models with identical aliases, I chose to work around the behavior by not using the @RequestBody annotation in one controller, and injecting (or creating) a separate XStream instance with only the appropriate package's annotations processed. Since I know the POST will contain an XML body, I add the HttpServletRequest and deserialize to my alternate model directly.
