Samba and permissions

["Mark Sweitzer" <ms2k@email.com>]

I have a Redhat 7.3 system running Samba server for Windows98 networked
users. These users are registered users on the Linux box, using encrypted
passwords mirrored in Samba's password list. These users need to have file
ownership for existing and new files edited on their Windows PC's. To allow
this, I've made the following mods:
in etc/profile: umask 002
in each user's data directory: chmod -r 7775
in "etc/samba/smb.conf" global settings section:
create mask = 7775
inherit permissions=no
force create mode 0664

This allows proper file ownership, and I then set all files in each user's
directory to be "read only" to all users but its owner. It also allows me to
assign other group permissions as is necessary without disrupting the
ownerships. Sometimes though, a user will copy a data file from their own
directory into another user's directory, with the intention of having the
file be "writable" by the 2nd user. However, the file continues to hold the
original ownership, and is "read only" to the 2nd user, even though it now
resides in the 2nd user's data directory.
I need to find the correct "chmod" command, or other method, to allow these
special files to become writable. It needs to be via a one-time command or
script entered at the server, as these Windows users do not have access to a
Linux shell, only to their Samba network shares.
I've also tried "inherit permissions=yes" but it did not correct the
problem.
Any suggestions?
***********************
Thanks,
Mark S.