Filter searched pages

Hi,
I’ve got a problem filtering pages by searching a keyword.
I organized WordPress in this way: there are parent pages, in which I put “Hospitals”, and their child pages, in which I put “Wards”. I’d like to organize the search on the website separating “Hospitals” (parent pages) from “Wards” (child pages).
Code that filters only parent pages is: http://pastebin.com/mNUSz9iV but it doesn’t work…