Outlook 2003 rule

We have a employee leaving the company and his e-mail is being forwarded to his old boss right from exchange.  He would like a rule to move messages from this old employee to a folder in outlook but when the fessage comes into outlook it is just delivered directly there and is not forwarded.  It has the old employees name in the to field but how do i make a rule to move these to a specific folder.  I didn't see a way in outlook rules wizzard to do this.