[Samba] What is the preferred way to inherit permission on a pdc?

[Aniruddha]

When you follow chapter 2 of SBE (
http://www.samba.org/samba/docs/man/Samba3-ByExample/small.html ) you
get a working PDC. However there is one problem: if you create a
document in a shared folder only the owner can edit this document.
Others in the same group can't edit the document and get a 'permission
denied' error. Permission are arranged with groups, new files get the
permission of the creator (which is is proper Linux behavior).

For now I solved this problem by adding 'inherit permissions = yes'
and  'force group = mygroup'  to smb.conf. I do wonder what  the
correct or preferred way is to handle these permission problems with
samba as a pdc? How do you make sure that files create by users in a
domain are accessible by every other member in the group? Thanks in
advance!