CS6 Multi-camera greenscreen & multicam monitor?

Question

Does anyone know if there's a way to do Multi-Camera Monitor editing, when the source footage uses multiple cameras against a greenscreen, when the greenscreen replacement layer is to be unique for each of the 3 angles?
I recently shot a few instructional videos in a greenscreen studio.  My setup was such that I had 3 cameras, for three different angles, and remotely-recorded audio.
Now in the process of editing, I've hit a bit of a wall, and was hoping for some help.
I'm using Premiere Pro CS6, and I've set up the project as such:
The sequence in the timeline has 6 video layers: 1 layer for each of 3 camera angles, and 1 unique background replacement layer for each camera angle.
Now I want to use Multi-Camera Monitor to do my angle cuts. The problem is that Multi-Camera Monitor sees the 6 different video layers as unique camera layers.
I want to know if there's a way to do multicamera editing such that I can lock each camera and background replacement layer - such that Multi-Camera Monitor sees them as one.
My first attempted workaround was to create individual sequences for each of the 3 angles give them the background replacement treatment, then nest each of these into a new sequence, and go from there. The problem I've found in doing this is that the audio waveform display for each of the individual sequence layers disappears (once they are nested in the big sequence) - so I didn't see a way to sync things up without an audio source.@
I *could* always create and export each of the angles and replace the greenscreen for each as it should be, export each of them, and drag these to the Project panel to use as my new "original layers".  Just seems like a lot of extra work, and that there would be an easier way to do all this.
Also thinking I could create a master source sequence (every angle, background replacement, audio, synced up), duplicate it three times and delete 2 of the camera angles in each, then combine each in a nested sequence with the audio, then make my cuts in yet another sqeuence with Multi-Camera Monitor.  Again, seems like this should be easier somehow.
Any advice would be very helpful.  I couldn't seem to find any answers elsewhere. Thank you in advance.

Answer 1

Thanks for the note. 
I thought about the first option - the problem is perspective (The background is slightly different for each angle, not uniform). And dragging the backgrounds to a BG layer later would be somewhat time intensive.
Nesting is interesting, but I've got so many of these videos, the Multicam Monitor way of editing together angles seems like it would be less work in the end.
Here's the workflow I think I'm going to go with:
Create a 'Master Source Sequence', and align everything. (Angle 1, Background for angle 1, Angle 2, Background for angle 2, Angle 3, Background for angle 3, Audio tracks).
Duplicate this sequence 3 times.  Delete all elements from each copy except for one of the cam angles, and rename each to 'Cam 1 Sequence', 'Cam 2 Sequence', 'Cam 3 Sequence'.
Drag each of these 3 to a new sequence, called 'Prep for Multicam Sequence'.
Drag this to 'Mutlicam Cut Sequence', drag in external audio tracks from 'Master Source Sequence', cut with Multicam as normal.
Again, thanks for the follow up!