Joint venture agreement

"If for any reason, the parties hereto come to conclusion that it is not possible or feasible to develop the said property jointly then this agreement will come to an end and in such event ABC shall be entitled to develop 2/3rd area of the said property and XYZ will be entitled to develop 1/3rd area of the said property independently and at their own costs. The division of the said property in the aforesaid proportion shall be decided mutually by the parties hereto." Its a clause from a joint venture agreement. What does the aforesaid clause mean? Does the division mean, of ownership of land or development? Also is it necessary to pay stamp duty & register a joint venture agreement?