what you want is possible in g2, but not the way you think.
negative permissions are not available in g2.
from your description i gather that you have at least 3 kinds of users.
- anonymous user
- registered users (your family and other registered users)
- your family
and you want that your family can only see a special album, but no other albums.
other registered users should see everything (or so).
correct?
then you have to introduce a third group, such that you have:
- registered users group (default, can't be deleted)
- family group
- other registered users group (new group)
- remove view all permission from the registered users group for all albums
- assign view all permission to the family group for the family album
- assign view all permission to the other registered users group for all albums
drawback:
you'll have to add each new user manually to the "other registered users" group.