Automatically connect VPN when using tethered connection?

Hi,

I have a MBA running Mavericks 10.9.2. I'm tethering on occasion with Tetherme on my iphone5. I subscribe to a VPN service (PIA). I'd like to know if there's a way to automatically connect the VPN on the MBA when I am connected to my tethered connection. The MBA uses a chainlink icon over the wifi icon in the status bar, so it does differentiate between a normal Wifi and a tethered one. I'm pretty new to macs, so I'm not sure if there's a way to do this. The PIA VPN does use an app (though I'm not sure this is necessary?) so it may complicate things. Maybe an applescript or something?

Thanks for any leads/advice/solutions you can offer to do what I'm hoping is possible.

-Chad