This has long been debated, but basically there is no way to do this at home. This is something that can be done by a replication company. Also seems to be a waste of money, since any 10-yr-old using free software can easily copy the disc anyway in a few minutes.
Put warnings on the video and the packaging, that's about the best you can do.
Thanks for your reply, I have tried explaining this to my boss but he insists that I look into it anyway.
Would you know if it is possible to prevent people from skipping to a title of the DVD in a media player? Not with "next chapter" but choosing from the dvd title list in the player. Or is that also something only a replication company could provide?