I don't think those four people are using the PC all at the same time, or..?
Then, as far as I know, what you ask is already standard facilitated by Windows itself, provided that you have Windows set up for several different users. Each user then gets its own Windows "environment".
When installing BS.Player, you select "Create Start Menu and Desktop Icons for all users" and "Save settings in user home folder".
(Of course, another possibility is to create
and save several playlists, which can then be loaded whenever a user wants so.)