Make it that you can have car keys for each car on a plot so that you can hand a car key to a certain car so that one person who has the car key is the only one to use it. So like at a car rental place or a dealership the owner should be able to "grab" a key from a car by clicking on it and has the car key and they can hand it to anyone. Also make it that other people can only be passenger that don't have the key and that the person with the car key can kick someone out the car. ( I really think this is a good idea since several people at once with perms is just really chaotic for me and they can just take other cars that you have so I'm recommending this since car theft in Bloxburg exists :/ )