redirect ssh user to another host
 

hi all.

I've got VirtualBox running guest Linux os,
network type is bridge, attached to local network interface
(so guest os is kind of in internal network).
I need several users to be transparently forwarded from
server host to guest os.

my first attempt was this script instead of shell+public keys auth:

#!/bin/sh

exec ssh user@guest.os.address.here

but that doesn't allow sftp/scp :( doing scp/sftp on such user
simply hangs.
I know I can simply forward port with iptables, but I would
like to make sshd to forward connections to remote host.
is it possible?

P.S. google doesn't help at all :( it shows x11, port, tunneling
forwarding, but not full ssh proto :(