The point here is that the admissions committee is trying to figure out how you relate to people. It doesnt matter if it is a personal relationship (something in your home life) or a professional relationship (something at work). What they are looking to see is that you have the skills to relate to people, to communicate, to help them through problems, etc. You absolutely can talk about the time when you had your staff solve a problem at work--but you need to focus in the essay on the interactions you had with the staff. HOW did you speak with them? How did you inspire them? What was that interaction like? That is the key--the personal interaction. What was the nature of that interaction--whether personal, or professional. Hope this helps!