Permission/ownership change with save

[FongV at sequus.com]

We have some files on our Samba-shared directory which are accessed by
more than two groups.  All the groups can read and write to the files.
We're noticing some quirks with some Windows applications, particular MS
Office 97 and Visio Pro 4.5.  For example, when a MS Word 97 file that's
owned by UserA/GroupA is modified and saved by UserB/GroupB, the owner
of the saved file is changed to that of the last person that edits it
(i.e. the new owner is UserBGroupB).  What we want is for the owner to
remain the same, i.e., the user and group ownership should belong to the
first person that creates the file.

I don't think this is a Samba problem.  I think the application is the
culprit -- MS Office.  When an MS Office 97 application opens a file, it
renames the original file (essentially creating a backup) and creates a
NEW file with the exact same name as the original file.  When the user
saves the opened file, MS Office 97 (such as Word) deletes the backup
copy.  Essentially, Office 97 applications creates a new file even when
it's editing an existing file, that's why the ownership and permissions
change to that of the last person who edits the files.

Does anyone see a way around this?  As mentioned, what we want is for
the ownership and permission to remain unchanged, i.e., we don't want
the permission to change to that of the last person who edits the file.

Any help would be appreciated.