[Samba] Need help for samba share and unix group

[Sigit]

Hi all,

I configured samba version 2.2.1a-4 on linux RedHat
and many share folders for department.

this is the configure

d---rwx--- 13   account account  ..  .. Accounting
d---rwx--- 4    admin           admin     ..  ..        Administration
d---rwx--- 5    director        director  ..  ..        Directors
d---rwx--- 9    hrd             hrd         ..  ..      Hrd

[accounting]
         comment = Accounting Department Directory
         path = /usr/sharing/Department/Accounting
         valid users = @administration @accounting @directors
         create mode = 0660
         directory mode = 0770
         browseable = yes
[administration]
         comment= Administration Department Directory
         path = /usr/sharing/Department/Administration
         valid users = @administration @accounting @hrd @directors
         create mode = 0660
         directory mode = 0770
         browseable = yes
[directors]
         comment = Directors Department Directory
         path = /usr/sharing/Department/Directors
         valid users = @directors
         create mode = 0660
         directory mode = 0770
         browseable = yes
[hrd]
         comment = Hrd Department Directory
         path = /usr/sharing/Department/Hrd
         valid users = @hrd @administration @directors
         create mode = 0660
         directory mode = 0770
         browseable = yes

on this case directors should be access to all department,
but I don't now why directors only can access his folder

Can any one help please?

Thanks a lot