Outlook Express type folders for easy filing and storage of important emails - any chance????

Is there any way that I can create a filinfg system in eM Client similar to the one I had in Outlook Express. I find haviong things purely in date order is not good enough from an easy access and storage point of view, and whist I live the software this is a serious problem for me… iwould alaso like to import all my old emails from OE so that I do not have to maintain two systems for all my historic stuff - of which there is much…