Let’s say I set up 6 computers in a company with your program. One or two of the employees of that company want to access their computer from home. Can they log on to the same machine, with perhaps a different password, with their own (free) account?
Yes, you only need to place that system in a group and have access to that group to that two different usernames.
If that access is temporal, you can “share” the access for a time-limited period, just by sharing a URL to anybody.