|Why would you want to do this?|
The smart thing to do is to always have the router between your LAN and the internet. This way the firewall in it can protect your computers from intrusion. Going directly to one PC would leave that computer exposed.
Perhaps if you explain what it is you're trying to accomplish, we can help you find an easier, and safer, way to do it.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.