Here's a mini HowTo on the use of Bindfs is you are interested:
Try the following experiment to see how this works:
 Install bindfs
 Create a couple of Test directories
sudo apt-get install bindfs
*** Create a hidden directory:
*** And an non-hidden directory:
*** Use bindfs to mount one to the other:
Now copy a file to /Test. It's permissions will be 660 and it's group will be plugdev. To undo the mount:
sudo bindfs -o perms=0660:+X,force-group=plugdev /.Test /Test
Note: The only reason I chose plugdev as the group is that it's already available.
To make this permanent you have a couple of options:
*** Add the line without sudo to rc.local
*** Or, Add a line to /etc/fstab with a different syntax:
*** Or, The way I do this is with an Upstart Job which is in my opinion the most reliable and safest way to do these sorts of things:
bindfs#/.Test /Test fuse perms=0660:+X,force-group=plugdev 0 0
Create an upstart file:
With this content:
gksu gedit /etc/init/bindfs-mounts.conf
Once set by bindfs all files and folders created in, copied to, or moved to that folder will have group ownership of plugdev and folder/file permissions of 770/660 except for files that are executable - they will be 770. At this point no other process - not umask, not Samba, not even root - can change permissions on an individual file.
# Remount Directories with Bindfs
description "Bindfs Remounts"
start on stopped mountall
bindfs -o perms=0660:+X,force-group=plugdev /.Test /Test