This never got answered:

Quote Originally Posted by willpell View Post
Q409
How do Share Pain and Shield Other interact with Damage Reduction?
To clarify, if you and your buddy both have DR and you Share Pain with him, is the damage reduced twice? If you have DR, do you apply it before or after splitting the damage with your buddy? If your buddy has DR, does it apply to damage dumped on him by Share Pain even when you didn't have DR?