Thread time shut off

[trifive]

In my forum I have a Thread/subforum that welcomes all new members and they post their first hello to members.

The problem is some members look up old post in the new members thread/subforum and
say a welcome to them even if they joined a year ago.

So is their a way to make all post in this sunforum only close after so many days, so no new post can be made to a thread.

The rest of my forum I do not want threads to close or expire.

VB 3.7

Thanks

otis