i have a particular problem

There are several users connected to one main server, however the users are not in one room, in fact they are not even on the same floor, but they are all housed in one building.

There are a total of 25 users.

In the evening when I need to shut down the program to enable me to do backup and integrity testing I need to log off all the users.

At present I have to inform them physically, it is also possible that a user leaves for the day leaving his computer on.

how can I remotely log off everyone connected to the server, maybe through one click !