This system is called UUCP
--vadim
to the original poster:
as much as people like to laugh about UUCP, it still works.
UUCP over TCP/IP should do the trick. why not?
if you expect that it is often likely that there will be _no_
routed path between source and destination hosts, and that
queue-next-closest-available is what you want, i'd say UUCP
is exactly your solution.
smtp has way too much of what you don't need.
steve.