anyone know How to synchronize Excel Sheet over Network



ok

the story is , i have a shared Excel File on file server
me and my friends all access it

of course when someone open it first , he can do everything
and i only can open it as " read only "

what i wish is :
when i open this excel sheet as read only , then i make my changes in it
i wish those changes update the file , when it's available for editing
or when he close it