Word Press Blog customization of functionality

Current Word Press Web Blog in need of custom functionality. We need the following capability with our current blog program. Comments with reply posted to be sent to a selection of members when posted to our blog. Currently we have a plug in which will send the comment but not the reply, we don't want them to have to go to the website to view the reply and we don't want them to receive any other info other then the comment and reply we make to the post. We want to be able to add and delete who is on the list of receivable members to get this information.