It makes sense to me, however, I have to jump in for my own understanding. You are talking about image number 3 and in that image what you suggest will blow the windows and expose the man in the middle correctly which works perfectly for me but at the same time wouldn't the flash be much stronger on the much closer woman wearing the white shirt? After my recent photo shoot on Monday (just getting use to doing portraits) I will be the first to feel sorry for all those wedding photographers out there who are trying to balance a white dress and a black tux in afternoon sunshine!

For number 3, I would slightly overexpose the lady and slightly underexpose the man while shooting in RAW and then layer in two copies of the image. One processed for the highlights and one processed for the dark areas. Am I making sense? Is there a better way? Assuming of course, that you don't have off camera flash which I currently don't have.