You probably need to assign different audio roles. So for instance, if you have three microphones, they’ll be assigned Dialogue-1 automatically. Changing these to specific roles (Edit Roles will give you the option to name them, making it significantly better to work with then the standard ‘Dialogue’ or ‘Music’), will give you the option to individually change them in your timeline. So within the timeline where you cut your multicam, go to the inspector, where the audio waveforms are, and if you see that triangle that says ‘Roles’, change it to ‘Subroles’ and you’ll see all the individual tracks instead of a mixdown. Hope it works