[Samba] disallow change group

[Ludek Finstrle]

Hello,

  I have file "file" with ownership "student.teacher":

-rw-rw----   1 student teacher      xx Dec 28 2005 file

. I need to disallow user student to change the group for the file
"file" (or whole file/dir tree). I think somewhere could be vfs module
for it but I'm unable to find it. Or is there another way to do it?

server  - linux (debian stable) + samba 3.0.14 from debian stable
clients - winxp, linux + smbmount

Thanks for help

Luf