Offline synchronization started automatically only on one share

In one domain enviroment, on the same Windows 2003 server I created two share
folders and all turned on Offline Files. I didn't do folder redirection to
those two shares.

On windows XP client, I didn't do any change in Synchronization Manager. I
found that offline synchronization happened on one share when user logged
out.

I want to keep the Offline Synchronization enabled on both of two shares,
but turn off auto synchronization on clients, give the administrator right to
turn on synch to a few users.

I know there is an option "Enable Offline File" in Offline File in Windows
XP to turn on/off Offline, but I have more than 300 clients, can't do it by
manual.

Is there any better way to do it?

Thanks in advance!

I have disabled offline on both shares.