I don't think this is a good idea to share GPU/CPU devices like this. everyone will be experiencing reduced performance if somebody else has an attack running at the same time.
I also do not understand what files should be available to the different users, but I think that --session, --restore-file-path, --potfile-path and --outfile options could be very handy for you. You could just write your own wrapper that the single users can run, instead of launching hashcat directly and every user has some [username] within their --session name and also paths with usernames for the different users.
Of course it's a little bit work to write this wrapper, but at the end a small shell script should do it quite well.
Your situation is very unusual that users shouldn't manage their own software and should run hashcat at the same time etc. I'm not sure if this is a good idea, but maybe you have some good reason to do this that I can't think about right now.
I also do not understand what files should be available to the different users, but I think that --session, --restore-file-path, --potfile-path and --outfile options could be very handy for you. You could just write your own wrapper that the single users can run, instead of launching hashcat directly and every user has some [username] within their --session name and also paths with usernames for the different users.
Of course it's a little bit work to write this wrapper, but at the end a small shell script should do it quite well.
Your situation is very unusual that users shouldn't manage their own software and should run hashcat at the same time etc. I'm not sure if this is a good idea, but maybe you have some good reason to do this that I can't think about right now.