Locking down updates

At the moment, you can either have your updates/conversations viewable by everyone, or "lock" them down so that only those in your organisation can see them.

It would be useful to have more options - ie to lock it down to a specific external group of users (ie a creative agency), so that you can clarify comments from an internal stakeholder to an agency, but without the stakeholder seeing them. Or comments to an external agency provided by an external stakeholder.

As we're supposed to have all of our conversations in WF, it would be helpful to have more options for "privacy" of some sort.