Accepting Cookies from Only One Site on the Web?

Greyfox asks "With the new /. system in place, I want to accept cookies from /., but I still don't care to get them from the rest of the Internet. Is it possible to set Netscape up to do this and if not is there some proxy server out there that will do it for me, perhaps filtering cookies from every site that's not on a list specified in a config file? "