1. From the Control Panel, choose “Network & Internet.”
2. Click “View Network Status and Tasks.”
3. Click “Manage Network Connections.”
4. Right-click on your VPN connection and select “Properties.”
5. Select the “Networking” tab.
6. Highlight “Internet Protocol Version 4 (TCP/IP v4).”
7. Click “Properties.”
8. Click “Advanced.”
9. Uncheck the “Use default gateway on remote network” box.
10. Click “OK” three times to close the windows you opened.

For example, to add a static route to the 10.0.0.0 network that uses a subnet mask of 255.0.0.0, a gateway of 192.168.0.1, and a cost metric of 2, you type the following at a command prompt:

route add 10.0.0.0 mask 255.0.0.0 192.168.0.1 metric 2

Source: https://technet.microsoft.com/en-us/library/cc757323(v=ws.10).aspx