Hi. I have a Linksys WRT54GL wireless router, with my three PCs connected to it, 2 by Ethernet and 1 by wifi. I'd like to share the Internet connection wirelessly (I'll allow his MAC) with a friend, but I don't want him to access my LAN (the other three PCs). Can I do this with this router? What should I do in order to get this? Thanks in advance.