What I came up as purposes for each team are listed below.
Developers Team- Are the researchers and scientist of the Umbrella Corp. their reason to be here is for Testing out Projects and Viruses, they are also the ones that focus on creating new things for the Corporation including Viruses, Weapons, Projects, Drugs, and Anti-Viruses that fight against other Viruses.
U.B.C.S. Team- They are the ones that take mostly part on missions for the Umbrella Corp. they will be like the "Military Force" of the Corporation. Their job is to follow instructions from Generals and Leaders, and to handle the "War and Life Risking" situations, they are also the ones mainly trained for combat situations.
Medical Team- Well yeah they are Medics, in charge of taking care of our injured Employees and making sure they are cured for action. But their job won't be that easy, they will have to also be part of the missions along with all that goes around, when taking part in patrols, mssions, and other things they are to maintain with the others and help out in medical attention that is needed but also take the "combat" stuff like being armed and fighting side to side with others.