How to Classify an Import

Please help, my wife is pulling her hair out. She just imported a bunch of photos from her phone. She is trying to classify them by putting them in folders describing the event. She is doing this by dragging photos from the 'Last Import' view over into the newly created folders. However, once she drags photos over, they still appear in the 'Last Import' list. I understand the reason for this (because even though they are in a new folder, they are also still considered 'Last Import'). How can I create a Smart Album to show the 'last import' that has not been named in a photo or album? Can you classify an import?