We provide natural mechanisms for the Nash implementation of the Nash bargaining solution if the set of possible payoff allocations is unknown to the planner. The need for two different mechanisms arises, because the case of three or more agents and that of two require separate treatment. Agents' messages in our mechanisms consist just of a set of payoff allocations compatible with the status quo point, which is assumed to be known to the planner. Indeed, the message spaces can be further reduced, to consist just of pairs of a strictly individually rational payoff allocation and a binary signal.