TeamViewer with two NICs for double access

GioSomma

I have a PC with TeamViewer to which I connect to manage a network.
This PC is in the LAN, so behind a firewall.
If the Firewall is blocked, I can not connect to TeamViewer.

The PC has two network cards and I thought to connect one of these to the router, then outside the LAN.

The attached image can clarify the connections.

The problem is that I do not think this is possible. With two NIC TeamViewer only allows connection from the LAN.

How can I do?
Thanks in advance for suggestions.