[Zope] creating trees

I posted into the zope-dev list, but I think it was the wrong list for this. I am using squishdot. I currently have this code to display all the articles, and comments. <dtml-tree branches=postingValues> <A HREF="<dtml-var tree-item-url>"><dtml-var title></A> </dtml-tree> This works well, but I would like to be able to get a listing of the subjects as the top branch, and then the articles that are associated with the subjects as leafs. I think that would be real cool. thanks, geoff nordli