ValdikSS

client-to-client
client-config-dir ccd

--client-nat args
        This pushable client option sets up a stateless one-to-one NAT rule on packet addresses (not ports), and is useful in cases where routes or ifconfig settings pushed to the  client  would
        create an IP numbering conflict.

        Examples:

            client-nat snat 192.168.0.0/255.255.0.0
            client-nat dnat 10.64.0.0/255.255.0.0

        network/netmask  (for  example  192.168.0.0/255.255.0.0) defines the local view of a resource from the client perspective, while alias/netmask (for example 10.64.0.0/255.255.0.0) defines
        the remote view from the server perspective.

        Use snat (source NAT) for resources owned by the client and dnat (destination NAT) for remote resources.

        Set --verb 6 for debugging info showing the transformation of src/dest addresses in packets.

Мне кажется, что все просто, что нужно просто прописать дефолтные пути для сетей на эти интерфейсы.
Это так