Use transparency in PNG to make selection?

[Steve5D7C]

Is there a way to make a selection or mask using the transparency in a PNG texture that's plugged into a fill layer?

I'm thinking something along the lines of the way you can do this in Photoshop by Ctrl clicking onto a layer that has transparency to select only the pixels that have values.

I have numerous PNGs with transparency plugged into the color channels of fill layers being 3D projected onto my model. I want to be able to select or mask these areas so that I can create custom isolated roughness etc for them. Is there a way to do this?