Thanks for all the suggestions. For clarification on my specific problem, I uploaded an example image of what the colorized buildings look like. The ground floor might have a different use than the top floors (i.e. apartments on top of a store), and thus one building could have multiple colors.Each building is a group of floors, each floor is a group. Color is applied on the floor group, not inside it directly on the faces. Now imagine that same exact image except all floors in each building are white.
The watermark idea would not work for this purpose. Any suggestion that uses Coloring By Layer as it currently exists in the latest Sketchup removes the aerial photography from the geolocation feature; one would need to get a “textured image” for the aerial photography which defeats half the purpose of using geolocation in the first place). My feature request for selective layer coloring would fix that.
The last suggestion (color buildings by texture + rest colorize) can work for now in the interim. Thanks for your help.