How to sync position only one time, using Photon Networking

I want to do the following.
When a player joins the room, he should receive all the gameobjects’ (with a photonview) locations.
This should happen only once when the player enters the room.
How could this be implemented?

First of all all players in the room need to have their own unique interest group they have subscribed to. The interest group can be changed by calling photonView.group. Keep in mind that this means that there is no synchronization at all until all players having the same interest group again.
Secondly you have to implement the OnPhotonPlayerConnected(…) callback which is called whenever a new player joined the room. Within this callback you can yourself call a RPC or raise an event on the newly connected player. Read about both methods over here.
Lastly implement a RPC or OnEvent callback. Within this function find the matching game object of the sender and set its position.