File ownership won’t change after ‘save’

We use to have a Novell 5 network and file ownership would belong to the creator of the file, then when it was edited and saved by a different user that user would take ownership of the file. In other words who ever saved it last owned the file, regardless of who created it. Now we have moved to a windows 2000 server (was sp2 now sp3) and domain. I’ve noticed that the file ownership doesn’t change after a save. So if a file is created by user ‘me’ then edited and saved by user ‘you’ the file ownership still belongs to ‘me’. Does anyone know how to correct this situation? I noticed that the same happens on a win2k pro station as well.