[Cin] Multiple viewers (like mixer, but without it)

I have multiple video tracks. I would like to play them simultaniously. Is it possible to assign a viewer to a track, without going through the mixer step initially? Preferably I am looking for an output that does take in account the applied plugin, but does not do downward compositing (or the latter should be configurable). This is the documentation for the multi cam mixer; <https://cinelerra-gg.org/download/CinelerraGG_Manual/Multi_Camera_Mixer.html> It is mentioned "Using the track patchbay, mark the new tracks as mixer source to be added to the viewer." I fail to see how I could mark it (or if this is the correct approach). -- Stefan