One login for many users

Thinking to make website for our choir. We need to share sheets of notes, audio recordings, so Kirby will be perfect for that. The only question, we would need to hide some information, so there should be login, but to make it for every member would be quite problematic, as people come and go, so best would be one single login, even without email, just password, that is same for everyone, and only admin could change it. Is there some easy way to do that, or would requite custom plugin?

If you do a front end login, you can hardcode a user email in your controller.