If I am a member of multiple networks, how can I force my Mac to connect to the Internet through one specific network? I have a Macbook and a Thunderbolt display. The Thunderbolt display is connected to a network with a very tight firewall. I also have a WiFi connection that is always connected at this location. The WiFi firewall isn't as aggressive and every now and then I need to connect to it to connect to a SOAP web service that operates on a blocked port.

Is there a ways (hotkey or system preference) that I can toggle so that I can remain connected to both networks, but force my MacBook to connect to the internet through the WiFi, rather than the local network?

Currently, I have to disconnect from the Thunderbolt display, and connect back up when I am finished downloading my data. Do I have any other options?
You can accomplish this without having to change between both networks. Connect to both networks. From the command line run these two commands.

    sudo route add -default *ipOfEthernetGateway*


That will set all traffic to go through the work ethernet link.

    sudo route add -host SOAPserver.com *ipOfWIFIGateway*


That will set all traffic that needs to go to the SOAP server to go through the WiFi link.