Splitting string

Hi all, 
I have a string like:
/this/is/a/test

and I need to create a template that will output:
/this
/this/is
/this/is/a
/this/is/a/test

I think this is not so simple as it looks at first glance.
Does anyone have an idea how to solve this problem?
Thanks for any help.

Rui
-- 
Rui Alberto L. Gonçalves <rui-l-goncalves(_at_)ptinovacao(_dot_)pt>
PT Inovação