Common Internet Traffic not thru VPN

[infraprmd]

Hi!

I got 2 Zentyals which are connected by Zentyal-to-Zentyal Tunnel VPN.

I Got Zentyal A network (NOC) connected to ISP A and Zentyal B nectwork connected to ISP B.

When someone in Zentyal A network hits the web, facebook.com for example, it does it thru ISP A and the problem is that when someone in Zentyal B network wants to check the same Web, instead of doing it thru ISP B, Zentyal B routes the request to Zential A network and Zentyal A server requests facebook.com webpage to ISP A and sends it back to Zentyal B generating useless traffic.

How can I set Zentyal B server to allow only LAN traffic thru VPN and internet traffic thru ISP?

Thank you!