You can go for Kevo convert which is a convenient and smart move because you don’t have to do major installation on your door. Kevo Convert make use of deadbolt and turns it smart in a matter of minutes — no need for hardwiring! Your lock’s exterior remains the same you only have to convert on the inside.
There are lots of smart locks in the market available today. For multiple users, I recommend Ultraloq UL3 Keyless Smart Lock that allows you to set codes to different group of users. You can even use fingerprint, code or key to unlock and you have full control of all guests’ access as well as share a code even you are not home.