Well you can model it any way you like: one objects, many bricks and windows, whatever. You can make the transition seamless by using a camera projection, and then creating a texture reference. That way when you animate all of your little objects, they will have bits of a texture map that come from the original piece. I recently hace to to a whole city block being torn down and reconstructed, and this was how I did it.

Is that clear or do you need me to outline the steps?