Just spit ballin…I wonder if you could unlink the clips from the media, modify the clips to be 5 channel audio clips and then relink to the audio recordings? I’ve done it the other way, where I import media from a camera with 8 audio channels, but only two of them have audio, so I’ve modified the clips to only have two audio channels and re linked to the media.
The other method would be to build a macro to do the heavy lifting for you. I have macros on my Avid Control surface and on my old G13 that would swap out audio on a clip by clip basis with the push of one button. Takes a bit to build, but it is definitely doable. for mine it was set to mark a clips inpoint, go to inpoint, match frame, adjust track patching on the timeline and perform an overwrite edit. (a bit simplified, but that was the basis) I used this to go back through a program and add in all the ambience tracks after the edit was done.
I hadn’t tried it, but in theory your macro could also do a “step forward 1 frame” to hit the next clip, and “repeat”, so essentially the press of 1 button could do the entire timeline. For mine, I simply clicked on a clip, hit the macro, clicked on the next clip, hit the macro…you can go through a good sized timeline pretty quickly.
Depending on your sequence layout you could do this on the existing timeline, or create a duplicate, build a timeline of only the 5 channel audio, and then cut that into your existing timeline.
Glenn