Outlook New Item Alert based on conversation in Category

Is it possible to get a New Item Alert to activate when an email arrives that has the same subject, i.e. is a part of a conversation? This would have to take into account any RE: or FW: that might not be in the initial email.

I have a Category that I put messages in when I’m waiting for a reply. It would be very helpful if the New Item Alert popped up when that reply arrives.

I don’t think Rules and Alerts will do this. Possibly VBA? Using Outlook 2010.