I'm a bit new to resolve. I'm transcoding files from the Sony F5 and Canon C500. In the media preview I can see audio 1 and 2 levels moving separately (one lav, one boom). I set output to render audio (4 tracks). When I look at the resulting file in FCP7 I get tracks 1 and 2 mixed together - both A1 and A2 are exactly the same (nothing at all on A3 and A4 but this is to be expected as the camera recorded on 1 & 2). I can not find any option for NOT mixing audio tracks.
Check the Audio Mixer settings on pages 342-343. You may be able to disable the tracks you don't want to hear in the embedded audio. The pan and send controls will allow you to place the audio tracks where you need them to be.