Mark the GameObject as a Static Occluder in the occlusion culling system.
For more information, see the documentation on the Occlusion Culling system.
void StaticEditorFlagsExample()
{
// Create a GameObject
var go = new GameObject("Example");
// Set the GameObject's StaticEditorFlags
var flags = StaticEditorFlags.OccluderStatic;
GameObjectUtility.SetStaticEditorFlags(go, flags);
}