give permission "edit" post for a group
 

Hi,

My forum currently set for everyone can edit their own post in 30 minutes, after that they can not edit their post anymore, only Moderator or admin can edit their post.
Due to so many link and post changes, member request to give them permission to edit their own post. So I create a group called " Special members" and only allow a member who is in this group can have permission to edit their own post, thread. Right on the group managment I have checked "Yes" to allow them to edit their own post but when login to forum, those members still can not see the edit button. So how do I setup that can only allow this group have permission to edit their own post?