A person may attach a condition to his eruv and say, ‘‘If gentiles come from the east, my eruv is to the west; if from the west, my eruv is to the east; if they come from both directions, I shall go to the place I choose; if they do not come from either direc-tion, I am as my townspeople.’’ ‘‘If a scholar comes from the east, my eruv is to the east; from the west, my eruv is to the west; if one comes to here and [one comes] to there, I shall go to the place I choose; if to neither direction, I am as my townspeople.’’ R’ Yehudah says: If one of the scholars was his teacher, he must go to his teacher. But if both were his teachers, he may go to the place he chooses.