from otree.api import * doc = """ Your app description """ class Constants(BaseConstants): name_in_url = 'gbat_keep_same_groups' players_per_group = 2 num_rounds = 1 class Subsession(BaseSubsession): pass class Group(BaseGroup): pass class Player(BasePlayer): pass class GBATWait(WaitPage): group_by_arrival_time = True @staticmethod def after_all_players_arrive(group: Group): for p in group.get_players(): participant = p.participant participant.past_group_id = group.id class MyPage(Page): pass page_sequence = [GBATWait, MyPage]