[Zope] How to concat values in a list?

I want to have the following on each page: You are here : _Home_ / _Subfolder_ / _Page_ Where each of the components is a link. The dtml-in tag lets me iterate over PARENTS but how do I concatenate with each itereation ? I've seen that Zope shows this in the management screens. Is this some built in function? Thanks, Shalabh