14-1303. Venue; multiple proceedings; transfer A. Where a proceeding under this title could be maintained in more than one place in this state, the court in which the proceeding is first commenced has the exclusive right to proceed. B. If proceedings concerning the same estate, protected person, ward or trust are commenced in more than one county of this state, the court in the county in which the proceeding was first commenced shall continue to hear the matter, and the other courts shall hold the matter in abeyance until the question of venue is decided; and if the ruling court determines that venue is properly in another county, it shall transfer the proceeding to the other county. C. If a court finds that in the interest of justice a proceeding or a file should be located in another county of this state, the court making the finding may transfer the proceeding or file to the other county.
Arizona Legal Code