phpbb Message body hiding

[Imperialdata]

Hope this is the right section to ask this.

I need to hide the message body on a post in a phpbb forum and enable it for certain users only. How is the best way to achieve this? The only mods that exist are for hiding complete forums and not individual topics, even then it is only the message body that I need to hide, not the topic title.

Hope someone can help, thanks in advance.