Is it possible in DNG 6.0.2 to lock an artifact on the stream while requiring change sets for changes?

We are piloting the usage of Configuration Management in DNG 6.0.2 at our company and I have run into an issue that I am not seeing a way around.  I can manually lock an artifact in a Stream and it prevents others from making changes in the stream or delivering change sets to the stream while it is locked.  That is all good, but if I want to enable the restriction on the stream to force users to make changes in a change set, I don't see a way of acquiring a lock on the stream.  This allows multiple users to make changes to the artifact without realizing that someone else is making changes at the same time.  This makes an even greater chance of having conflicts on delivery.