I was facing a similar issue though it considers the physics of dynamic rigidbody entities/objects in the scene instead of players. I haven’t solved it quite yet but things are getting warmer thanks to an approach I dug up in the forums last night.
I’m using an approach found here which utilize’s an entity’s unique Guid value. I find the entities I want by setting a tag on them and loop over all items with such tag. With that you should be able to send the name of the entity and it’s position or any other state you want to the network.
this.entity._guid;
Like @leondias stated, physics stuff should remain on the client, though utilizing the tutorial realtime multiplayer example this physical player interaction happens naturally yet has room for personal tinkering.
Hope this helps in some way!