Okay, when dragging and dropping res, it does finally ask if I really want to copy AFTER it takes quite a while "extracting". I was confusing extracting with unzipping or unpacking...or some other term that would imply it was changing the format. I'm still not sure if it's doing it properly, but I'll keep trying. And I'd still like to know how to make these combined posts cause a notification, and if not, how can I force it to.
The combined posts happen depending on the time between replies to different comments on the same thread. It's automatic.