Can't disable Plugins for non-supporters

How do you disable plugins for non-supporters? I've had three installs done by WPMU and they all do the same thing. When I enable plugins on the site>admin>option page, all users (support and non-supporters) can see and use the plugins.

Isn't there someway blog plugin access for non-supporters? Everything else works as it should, data upload is limited and remove ads is disabled for non supporters.

Thanks,

Daryl