Unfortunately, at least that I'm aware of, (I am new at this), you can't select objects to be hit by lights in DS. (You can make objects not cast shadows, and be invisible, but not block specific lights from hitting them.) Also, I think to have light fall-off you need to buy the UberSpotlights, from what I've been able to gather.
I recently watched a video about lighting from Dream-lounge that demonstrated both those features in Lightwave, so I can definitely see how useful both features would be, so if they are in DS4 I'd love to find them.
(And UberSpotlights are definitely in my wishlist.)