Extracting Surround Sound from HDMI Signal....

Hello!

My wife is technologically challenged so I have connected the HDMI outputs from my ATT/Uverse box and Apple TV box directly to the TV. This makes it simple for my wife to use as she doesn't need surround sound for most things. (The TV is an older Mitsubishi rear digital projection model with two HDMI input ports.)

This is all well and good, but because of the handshaking between the TV (which will only recognize stereo audio) and the two boxes, the HDMI outputs from the ATT and Apple boxes default to PCM stereo. And even though I've got optical taps from both boxes going to the optical inputs on my Marantz receiver, the receiver only gets a PCM stereo signal, because the TV is telling the boxes that it can only process PCM stereo.

So, is there a way, a box perhaps, that I can put between the ATT/Apple boxes and the TV that will extract a surround sound signal that my Marantz can utilize and still provide stereo sound to the TV?

In other words, I'd like to have the TV work on it's own with stereo sound and not require my wife to turn on and fiddle with the Marantz receiver. And then, if we want to, simply turn on the Marantz and add surround sound to the mix.

Thanks for all suggestions!