If you want real transit transfer of packets, you'd rather configure
uugetty to tunnel fidonet calls directly to the os/2 machine. Routing
of *packets* is not easily done with ifmail. Although, you may
gateway netmail and echomail, and then route it back to ifmail (to
another node) with unix means.
Another option is to write a script that would move packets from inbound
directory to outbound. But this may be quite a delicate task.