Sharing a directory

[Jonathan Wheelhouse <wheelhouse@exemail.com.au>]

Got a question re UNIX permissions: I've got a directory, photos, in
my home directory, that I want the wife and kids to put digital
photos.

I created a group, photo, and put them all in it.  I changed the group
on the directory to be photo.  I set the sgid bit on the directory so
that files created in the directory will have that group.  I set the
restricted deletion flag on the directory so that people can only
delete their own files not those of others.

Now the problem is that if people create sub-directories in this
directory and then populate that sub-directory with photos only they
have access to those photos.  How can I make it so that even if they
create sub-directories the files in the sub-directory have their group
set to photo?

--
Jonathan