If all of these multiple users are logging onto root, which is just one account, then you cannot track each individual person login on unless they keep track by using a sign-in sheet of when they are using root. But I don’t see this working at all, because once you start working, you should be in the zone, and having to put your name and time on a piece of paper is not a priority.
Also, why so many have access to root? That is way too many cooks in the kitchen. You are an accident waiting to happen because no one is going to admit when something happens, especially if it will cost them their job.