Add "bleed" or "padding" to brighter parts of a texture


I am creating a parent material in Unreal in which I will input several greyscale textures later.
To counter some baking Issues I had, I am trying to add kind of a bleeding to the textures, where only the brighter parts bleed over the darker parts of the texture, without changing the overall intensity of the textures.

so basically I want to make this:


to this:


Is there an easy way to achieve this with the unreal material editor?