[Zope] dns(?) question

I have an internal linux machine running zope and a freebsd firewall running ipnat/ipfilter, dns, and apache. I would like to set zope up so that a) people can access it, and b) so that people can just type in "zope.silentcooperative.com" and have it redirected to the proper machine. I don't want to use mod_proxy, squid, transproxy or apache at all for that matter for the redirection. Can I do this in DNS in conjunction with NAT or is there a low overhead suggestions for doing this??? thanks, chris