The answer is No I'm afraid. The Flex Eight is a 2xIN (stereo in), 8 x OUT DSP configuration when it comes to the Processing Chain. It's not a multichannel interface (i.e. 5.1/7.1). 

The SPDIF/TOSLINK input is also only for Stereo. SPDIF/TOSLINK from your TV that might be "multichannel" is Dolby/DTS encoded. Only a Dolby/DTS decoder, i.e. an Audio Video Receiver/Processor (AVR/AVP) will be able to help on this application.