vBulletin 3.5.2 hack

We are looking for someone who can make a hack for vBulletin 3.5.2 to perform the following: 1. File uploads in specific threads can only be allowed by the creator of the thread or by anyone who belongs to a specific group. 2. The file attachments can only be viewed for download by the creator of the thread or by anyone who belongs to a specific group. Please contact me if you have any questions about this. I require this rather urgently. Thank you.