photon server RPC to client

Hi.

I'm currently using photon cloud. And trying to use photon server for load balancing. How can I RPC to client?

in client's script, I can do this:

 [PunRPC]
 public void OnStartGame()
 {
     PhotonNetwork.room.open = false;
     PhotonNetwork.LoadLevel("Main");
 }
 public void StartGame()
 {
     if (PhotonNetwork.room.playerCount >= 2)
     {
         photonView.RPC("OnStartGame", PhotonTargets.All);
     }
 }

but what about in server's script.... how can I do photonView.RPC("OnStartGame", PhotonTargets.All); this thing?