[Zope] Accessing tree-colspan outside tree tag

I need to assign tree-colspan to a page-wide global variable so I can use this value further down the page. i.e. <dtml-tree> Set "_['tree-colspan'] to a page-wide accessible variable. </dtml-tree> ... Now access it down here. <dtml-let> would work, but you can't have start a let in a tree tag and finish outside. It would have been if <dtml-let> didn't have a closing tag to limit variable scope. Thanks. -- Guy Davis