Email usage restriction

Hi All

I need to restrict our users from sending too large emails. I dont know if there is a way to do this but the normal users must be restricted in a certian way and then I must still allow the directors to have no limit?

Could someone please help me with this

Thian

I'd be interested in doing this also, I know there is filters to set up such as senders/filesize etc., but it doesn't seem to work for me too.