[NTG-context] synopsis / column(set)s?

Hi all, I am trying to make a synopsis, i.e a text where in the leftmost column the original document can be read, in the middle the changes and in the right column the reasons for the changes. So basically I want to typeset first some text in the leftmost column (over several pages, on a grid), and then the one in the middle and then the one on the right. Is there an easy way to do this using column(set)s? Any help greatly appreciated ... Greetings, AleX