Hello Ron,
Can you be more specific to what you're attempting to achieve? I'd like to know the specific use case where you would list the end users mentioned, if you are performing one of the automated notifications or doing an on-the-fly manual notify.
I can envision a simulated notification functionality that works as you described. You are doing a manual notify and you do an arbitrary selection of end users to notify against, or you are doing an Initial Activity Notify and in the notification template, under the contact tab, you have specific users being notified each time.