Just a quick question.

Clarification and more information would be extremely helpful.

Network bridge maybe? Bridging (networking) - Wikipedia, the free encyclopedia

Most of the time when you join two networks over a VPN it is to secure a connection, say between two offices in different cities. Another great purpose of a VPN is to allow users to have a portable computer that connects to the network from anywhere in the world, this way they can work as if they were right in the office.

What is your goal in this?