Group By in acts_as_ferret

Hello,

can somebody tell me, if I can use the “group” option with
acts_as_ferret?

I want to find out in which categories and manufacturers categories the
results are in and show it on the left side (like amazon and eBay).

Look here:
http://search.ebay.com/search/search.dll?from=R40&_trksid=m37&satitle=canon&category0=

Best regards

Lars