Mecanim partial culling?

Hi,

I understand that mecanim can cull animations for objects that are not rendered. Is that applicable to whole objects? Or partial culling also? I have a game controller to switch between orbiting 3rd person camera to behind-the-shoulder views. During BTS view I'll mostly be seeing only the back of head and part of shoulder, and arms. It looks like a waste to let the lower half of body animate fully.. Or, should i create a separate animation mask for BTH view?

Thanks & Regards Raj