3D & Animation Optimizing Depth

[gunslingor]

So, part of my map is a movie theater. As you would probably guess, this movie theater is filled with chairs. When the player is standing close to the stage or screen, he/she is looking through all those chairs and performance starts to suffer. the player can always see the tops of each chair when looking in that direction and standing by the stage, but the rest of the mesh is obstructed by the other chairs in front of it. What I would like to do, which I don't know if it's even possible, is to only render the parts of the chair that are visible (ie the tops) and not the rest; I mean, there's no reason to render it since you can't see it from that angle and performance needs work. I still want the player to be able to walk down the isles, so the chairs need render better based on visibility.

Any other ideas or suggestions on how to optimize this situation?