phpBB forum mods

Was wondering if there was a mod to the phpBB forums which would automatically concatenate 2 posts (if made by the same user within a certain amount of time) into one post?

I've been having problems with people making threads and replying to it themselves to up their post count, but don't want to go through the hassle of deleting each one.

Any help would be much appreciated.

In the configuration page in the admin section, there is a a setting for Flood Interval Number of seconds a user must wait between posts. You could increase that time.