I would start by using the web interface and go to Advanced-> Users / Groups and add a user for each family member. Next I would create a group for each family member AND a group named Public. Next, I would add each user to the the proper group with the desired Read/Write permissions. When done, the Group List would look like the following.
NO. Group Name User Name
1 Father Father
2 Mother Mother
3 Daughter Daughter
4 Son Son
5 Public Father, Mother, Daughter, Son
Under Windows you would need to create 5 Mapped drives with the drive letters F:, M:, D:, S: and P:.
I would hope that Windows would allow you, as Admin, the ability to restrict the drives that can be accessed by each user.
This should get you started.