Disk Quota per files? Not per disk

If I have a server with a 80 gig drive. It has shared public folders and a profiles folder that has users private home folders. I want to be able to limit the size limit of the users home folder to 2 gig but let them use as much space on the other shared folders. This is all on the same volume/disk.

It seems that I can only do it per volume not per folder. Am I wrong? or can 3rd party software work?