You can run the 827 in "NAT on a Stick" Mode.
(http://www.cisco.com/warp/public/556/nat-on-stick.html)
This will do exactly what you want (running NAT using 1 interface only).

Thanks
Craig

-- 
This message is part of the NZ ADSL mailing list. 
see http://unixathome.org/adsl/ for archives, FAQ, 
and various documents. 
To unsubscribe: send mail to majordomo@lists.unixathome.org 
with "unsubscribe adsl" in the body of the message