Multiple masks to make a combined Outside Node

I have a parallel Node with 3 different nodes for face, jacket & shirt. I've used Qualifiers and power windows to create individual masks/keys. I want to now adjust the background behind them by combining them and then inverting the masks. Obviously I can create an 'Outside Node' (eg...face) for one of them but how do I combine all three into one big mask and then add back the original background to alter as required.

How do I achieve this effect?

Cheers
Andy

[Dmitry Kitsov BMD]

Hello, Andy,
You will find the Key Mixer node of a benefit as well as the Key panel in the color page of the Node receiving the result of key mixing operation.
See image attached for a sample node tree.

Key Mixer

2015-06-05 04.41.41 pm.jpg (163.73 KiB) Viewed 6490 times

I also find it quite confusing organizing excluding and including shapes whilst having a qualifier all in one node. The key mixer would help with this, but for some reason I always end up trying to do it in one node. There seems to be an abundance of invert and mask buttons both on the shapes and on the qualifier and mask output. Would appreciate if any of you big smoke colourist would share how you figure this one out.

Let's say you have a circular window that garbage mattes a qualifier, and then you need to include two details with two separate beziers because the qualifier is masking those details out.