Sharing files between users

[Vitaly Lipatov]

I am looking for any resolve a problem with sharing open files.
When one user  calls CreateFile with sharing=FILE_SHARE_READ, other user can 
open the same file with sharing=FILE_SHARE_WRITE wthout any fails. I know 
sharing control done in wine-server, but it resolves problem only when single 
user sharing  files, not two or more.
I guess to move sharing support in kernel in some way. Any suggestions?