I think I managed to solve it and I share the tip here for anyone looking for the same thing.
We know that peerid always changes in each connection, so I created a synchronized numeric variable and asked the player for a password that will be the identification of that object.
Then we have:
Player > peerid = c4g8
Owner= 9876
So everything that belongs to the peer will be named with this password "9876"...
On the client side, it is now easier when he connects everything that has this password to the map and copies his peerid. He now has possession of the objects.
My game in progress. Multiplayer online strategy game.