Yeah, Just use Lerps (Linear Interpolate) You'll need to think carefully about which order you're going to put things in as each Lerp can only blend between 2 inputs so with a mask map using all 4 potential channels you can blend upto 5 different maps. Also, be sure to throw out the blue channel and add the R and G…
Lerps can be useful but very tricky to control with blended colors, like magenta. You're better off composing your masks from just RGB and A channels. However if you wind up needing more than 5 maps you can build a color masking material function like this: ColorMask is your mask image ColorCompare is the color to select…