Is there any way to find a detachable trolley to add to a briefcase?

I have a briefcase which I received as a present (http://www.etsy.com/view_listing.php?listing_id=23720094) but being female, I am worried it is too heavy for me...especially when I carry books. I personally love another trolley bag I have, and am wondering if detachable trolley like systems might be sold anywhere, so I could just put the bag on the trolley, and remove it as and when the need arises, and wheel it home etc. I wonder if such inventions exist? :p