I think its definitely better to work with the people who have more knowledge on their department. As Dr. Schesser has metioned several times in the begining of the capstone project choose a person from each biomedical branch. This is necessary because while you are working on a project, you might start hating your friend. If he has different work standars than you, and then you will lose that person as a freind and you will not get your project done. However, if you choose a person who is knowlegable in that specific department, then you get a good group and you can force them to work if they are not doing their job.