How make all layer masks of different layers on GIMP affect just one layer?

Question

I'm colorizing black and white pics. At first I started just creating one layer over the black and white pic, setting the layer mode to "overlay" and painting with a normal brush. Then I realized this method was kind of difficult and I started creating a new layer for each color, using the bucket fill in the image and create a layer mask, so I could change the colors without erase them.

The problem is: everytime a layer mask overlays another one, it creates a "new" glowing color in the intersection. Is there any way I can use where those layers affect just the black and white pic? And then in intersections the color is the defined by the layer on top.

https://i.stack.imgur.com/1BjCn.jpg here is an example. I need a way I can use layer masks but without creating that intersection of the lips and skin colors. I need this because usually lips, hair and eyebrows have to be very smooth, smoothness which I can just achieve by overlaying, so I can't just erase the layers. I hope you guys could understand, thank you all!

Answer 1

Copy-paste the part of the B&W picture that should have its own color to a new layer, then create a group with that extracted layer and a color layer on top of it. Move the group to the top:

The effect of the group is limited to the opacity of the bottom layer.