I am not sure why you want them to know the status of the message. The nurse probably hasn't even changed the status. While things that take a long time like referrals as you wait for the date and time and insurance, etc., those who do referrals will continue to pull the message from their inbox, document, and send it back. I can see it anytime by logging into their account. We all use the same password. Just one letter.
Now, as an example, your front staff sends a message for the nurse saying that Mrs. Impatient who is soon to be Mrs. Inpatient has called wanting her lab results, or a refill or whatever. That is it for them. They are back to scheduling, checking in and going on Facebook.
The MA/Nurse is now dealing with the message either by him or herself or more likely, sending it back and forth to the doctor to get information.
So, when Mrs. Impatient who knows you close at 5PM but insists on calling at 2PM even though your staff told her your MA or they would call with the necessary information, they should just tell her, "She hasn't had a chance to get to it yet. When she does, she will call you as soon as she is able."