3 answers
You cannot. Notes and Attachments are directly tied to the object they show up on. So the security is based on the object they show up under.
You would have to creat e you own custom object and then do your own security on that object. Then on that object allow notes and attachments. So it would be clunky but a way to do it.
If not the above you woud have to do your own Visualforce development.
