Server without port forwarding.

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i'm using unity + photon. Is it possible to set up game that any player can create server(max 4 Player) on their pc and any other player can join without port forwarding or connect via program like hamachi (something similar to Left4Death or Payday2)? If is possible, how to set this and if is not, can player create server on something like photon server? How much cost something like that?