Disallow private and confidential information on posts by users and collaborators.

I have people posting private and confidential information about living persons on my family tree. I have blocked those users from submitting anything else but I have no control of what they post on their site. The information contained in these posts is private and confidential and should only be posted if authorized by the affected party (or parties). These posts include addresses, phone numbers and other personal information available on third party websites and obtained only by paying a fee. How can I control what is posted on my site besides blocking a person? I blocked the person but the system will not allow me to delete the post. Thanks.