Is it possible to drag and drop between iframes?

url in question is - www.teacher-share.co.uk/vle/teacher/main.php

there are 3 iframes on the page, one for the left bar, one for the middle and one for the right.
When a user creates or edits a lesson, i would like it to be possible to drag the resource from the right to the middle iframe - to a space which will register it (store in database) then show that it has been added.

any advice would be welcomed

thanks in advance