Setting Proxy for all IE 6 users once (W

I have a Windows 2000 Server DC PC, and clients with Windows 2000 Pro and Windows 98.
There are a lot of users created yet. I installed MS Proxy Server recently, and I want to use Proxy Cache.
I am trying to setup IE 6 with Proxy, from all users and in all PCs. I can make this change only to the account/profile that is mine. I want this change to affect all current and new users without having to make this change when they sign on. And if It’s possible without go client to client to make the change.
It’s that possible? What path I need to follow?
Thanks a lot

Josep M.