Skyr, here is an idea.... we recently tried to use the "group boxes" in messaging. So far, I have not found that it fits our particular work flow. This is primarily because the boxes are not organized the way we thought they would be. For example, I am a provider. So I would have thought that a message sent to "Group box (Providers)" would go to my Inbox. It does not. It goes to a separate box that I can access, but to see it, I have to go to the drop down menu that Wayne mentions above, in the messaging area, and select the "Providers" box. Not every user can see that box. Note that depending on the user, different choices are available in the drop down menu. So only certain people will see certain boxes.
So how does this impact on your situation? Be sure to go to EACH computer and look for the "Front desk" or "Front office" box. It may only appear on one computer.