Connecting an Xbox to computer in another state using an intermediary?

Question

I have traveled to a different state and want to connect an Xbox down here to a Win7 machine back in my home state for the purposes of being a Windows Media Center Extender. Normally, this is limited to a LAN-only situation, for bandwidth purposes I assume.

I have Hamachi set up in Gateway mode with 2 machines. Machine A is a Windows 7 x64 'gateway' (located in my home state) and Machine B is a Macbook Pro with OSX 10.11 and a USB Ethernet adapter connected to Machine C (Xbox 360) and a Wifi Network connected to the internet. Machine B and C are with me right now.

So, I want Machine C to be able to talk to Machine A over Hamachi (Or, any other network-bridging solution if a better one exists) through machine B. I have full and total control of machine A over VNC, as well as machine B and machine C locally.

Do you guys have any ideas what I'm doing wrong?

I've also tried (with the above topology and on the Mac machine):

ifconfig bridge1 create 
ifconfig bridge1 addm en4 addm ham2
ifconfig bridge1 up

and it didn't (seem to) work.