There are some good answers, here, but wouldn't you just be able to use something like a laptop, and be connected hardwired via ethernet, and connected to Wifi via your WLAN card simultaneously.
you might look into this application, I don't use it for anything nearly as ambitious, but it allows you to force a an application to bind to an IP address of a network interface.
http://www.r1ch.net/stuff/forcebindip/
I mostly would use it to connect to non-firewall friendly apps like spotify, by connecting my wifi to my company's guest network, while simultaneously remaining connected via ethernet able to work within the LAN. but you might be able to launch an instance of your application using this to bind it to the other network interface.