Can I have many users all using the same user account?

I have a section of a website that is to be visible only to members of the group. I have set it up so that you have to log in to see it so that works well.

There are 4 administrators and I need to add the rest of the group as able to view the private section but not edit it. The obvious choice seems to be to create a user account for each and set it to subscriber. Trouble is, there are 200 members in the group and that will take ages.

Can they all use the same ‘subscriber’ user account? Even if there might be 50 people all logged in at once?