Ability to "pin" Bulletin Board comments

On Member Group Bulletin Boards, every comment posted is deleted fairly soon, so important things, like ideas for group banners, can't be seen, and that can be pretty annoying. So I would like a way for the owner of a Member Group to be able to "pin" comments, like how Abbey can "pin" topics, so that they don't get deleted, and people can see them.
Please tell me what you think!