Force mask file creation in one dir
 

I need to force mask file creation in one dir.
Basically this is the situation
"document" is a shared dir, SGID is already set on the dir so all new files are created as group "office".
But they are created with 644 mask so they are not accessible by other users in the group.
I do not want change the default user mask with umask because of security reason, but I need that in this dir file are created with 664 mask.
Suggestion??

Dunno. One workaround would be to use a Dnotify or FAM client (better than a cronjob) to signal a file was created, and have that run a chmod script. If you're making the script yourself be sure to escape any weirdness: never trust user input.