any way to restrict private messages to those in the same usergroup?

I've been working on a concept for another forum, and for this one I want to be able to restrict sending private messages to other members in the same usergroup or those "below" it. Basically I want the usergroups to be hierarchical with the higher users able to initiate private messages to lower users but lower users able to communicate freely. I've been looking through vB.org and this one (Advanced Private Messages Options - vBulletin.org Forum) might be able to handle the restricting part but I don't think it would allow communications initiated by the "higher" member.

 

I've never heard of anyone doing this before. The system is set though so that Admins (and I think Super Moderators) can always send Private Messages even if a user is over quota. It does it with this permission: Can send PMs to users who have reached their quota.

Not sure how the hierarchy would work though. In Usergroups, vBulletin only has four levels in the hierarchy... Administrators, Super Moderators, banned users, everyone else. The only difference between Admins and Super Mods is access to the control panel. Banned users are a special case. The moderator usergroup is just a container and doesn't actually give any kind of moderator permissions. Functionally it is identical to the Registered usergroup.

 

Well, my idea was to create different usergroups to separate members based on number of posts, status, etc. Members would have to "work their way up the ladder" in order to be able to talk to or trade with the "higher" members. In terms of socializing on the open forum the vB software can already handle such "class distinctions", but not for private messages.

 

Obviously you cannot do this in default vb, and Ive never seen a modification that can do it either. The concept is similar to the Advanced Editing mod, where a higher group can (only) edit the posts of a lower group.