Only export sterio from 16 channel clip?

Hi,

I am having a little bit of problem.

I have a clip that i need to render for TV screening.

And no problem, Adobe Encoder can make the exacly format i need.

But this is 16 channel clip, the 5.1 mix is on channel 1-6, the 7.1 mix is on the channel 7-14 and finally the sterio mix is on channel 15 and 16.

How can i tell the encoder to convert the new file only only with the sound from channel 15 and 16 since the TV only want the sterio mix.

I can do this by load the clip into the Premire Pro and mute everythink exept channel 15 and 16 and then render it from there as sterio to the format the TV needs but i was hoping i could somehow skip the use of Premiere Pro and only use Media Encoder.