Message Tracking - Multiple Recepients

The message tracking feature of my board only seems to work when you send indivual PMs. However, when I send a PM to multiple recepients, it does not keep track of these.

Is this a bug or did I somehow screw something up? My board has lots of hacks, some in the private.php file, but neither me nor my other admin recall editing anything to do with message tracking.

Any ideas what it could be or how to fix it?

Thanks
Kit

[yzztik]

Anyone have any ideas? Am I the only one with this problem? :s