I have a group set with about three people in it
How did you set this up?
Why did you set this up?
It looks like you are trying to do something which already has a set method.
Usually, if you want to share your computer, you set up different user accounts for each user. This automatically gives users their own filespaces like you want.
If you want to have a shared directory for all users to access, then you can just create one which mounts to the users home directory when the user logs in.