Well, what you can do is make a new folder for older imported items.
If you RIGHT-click on an imported item, then click "Edit Item Description," you can manually type in a folder name in the Item Type box.
Once you've created a new folder, you can move items to this folder by click-and-dragging the item to the icon of the new folder. Unfortunately, you will unable to select more than one item at once. To save yourself some time, you can tell your MA to file all items older than mm/dd/yy into the new folder. Remember, you can name it whatever you want.
