Supplement. Deny reply to topics created by other users.

There is a forum to vBulletin which experts help victims remove malware from their computers. In order to avoid non-professional advice in the help section can communicate only "victims" and helpers.
Restriction organized using standard vBulletin (Can Reply to Others' Threads). The user can only respond in the theme that he created.

By the essentially of this topic:
I turned to for support XenForo asking to add a similar function in a great product. I was told that if this functionality will be of interest community, the functional can be expanded.

It is interesting whether community to respond in prevent others themes?

P>S>My English is so bad? :)
Sorry for resurrecting this thread, but I would like to see this feature or an add-on that accomplishes the same thing. We are migrating from vBulletin to XenForo and don't look forward to losing this feature in vB. I have one forum (node) that I allow the thread starter to continue adding posts, but don't allow others.