Create a positive mask in video editing I'm doing a video edit for a special effect of explosion and I'm encountering a little problem:

I did a mask around a car, to make the car visible in front of the explosion, but, like the majority of cars, this one has windows. That's why I created another mask for the windows, but here comes the problem:

I do not know how to "mask a mask", i.e. making holes in a "parent" mask (the car's one) that would sort of "cancel" the parent mask for this specific zone. And the few masking tutorials on the internet do not cover this.

So, if anyone knows the answer, I'd be happy to hear it, by the time, I'll continue to tweak with the color mixers to see if I can approach something good.

Thanks in advance :)
Got it!
A simple subtract node works well, you can even change the factor to change the opacity of the windows...

Sorry, this was a kinda useless question...