I tried a workaround that seems to be effective. Connect to the outside IP address on your LAN clients instead of using the internal IP, and it seems to fool MC into thinking that the LAN clients are actually WAN clients.
i.e. if your internal server is 192.168.0.1 and you have port forwarding on your router, and your router external IP is 66.222.111.123, add a new server using the external 66.222.111.123:25565 address on your internal clients.
This workaround works on a Apple AirPort Extreme but other routers may handle this differently.
JHeil
I tried a workaround that seems to be effective. Connect to the outside IP address on your LAN clients instead of using the internal IP, and it seems to fool MC into thinking that the LAN clients are actually WAN clients.
i.e. if your internal server is 192.168.0.1 and you have port forwarding on your router, and your router external IP is 66.222.111.123, add a new server using the external 66.222.111.123:25565 address on your internal clients.
This workaround works on a Apple AirPort Extreme but other routers may handle this differently.