You could in principle use views for this, but you can also limit what the client applications see when they browse the address space normally.

If you are considering the implementation with the Java SDK, you can filter the references that are returned for the client application in a NodeManagerListener.onBrowseNode(). You can use the provided serviceContext.getSession() to verify the calling client application (getClientIdentity()) and the user account (getUserIdentity) and determine if the reference should be visible or not. The View is also provided as a reference to the method, but I don’t know yet clients that could provide the View in practice so it may not be very useful, yet. Well, for your own system it might still be handy, though.