Am new here so excuse me if my question is naive! I have a terrain-filter raster in pink and another raster filter in purple (shown overlying the first). I am only interested in the areas where the pink and purple are connected. In other words, I want to remove all the purple areas that are not associated with (adjacent to or overlayed) the pink regions, leaving just the areas where the two filters touch. I then want to merge them together to make a filter combining both (I do not need to separate the pink from the purple - I just want to identify regions where the two filters are connected.