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