isolating lighting for a single object

I have a large scene with a lot of objects illuminating and reflecting off of each other. I wanted to light the background objects a bit better so i threw in some lights and used the 'scene' tabe to include the objects i wanted. As soon as I did this however basically all of my specular reflections in the whole scene disappeared.

Does anyone know why this happens and what to do about it. I dont really know too much about lighting so any info would be very helpful.

Thanks!