Finer control over issue visibility/permissions (BB-3883)

I want my Issue tracker to be used publicly but don't want people to be able to see other peoples bug reports also because they have my names attached to issues I report which doesn't appear in the "Assign to:" value but does in issues I have posted internally... It would be great to have an option to stop anonymous issuers from seeing issues list... and even being able to manage people who can assign to specific developers and attach files because I don't want anonymous individuals seeing attached files when the repository is private.