Alternate URL for NPM and alerts?

I have a DNS alias setup for my NPM web interface to make it friendlier for support staff than the servername. Plus it makes it easier if I need to add a second web interface server.

How do I configure NPM to see that alias as it's URL for when it sends out alerts or the like?

For example, I have an alert set to send the ${GroupDetailsURL} but it sends the servername rather than the alias.