As to the strict question of whether the Sunday obligation is fulfilled, the answer is yes, especially if people have no other Mass to attend. As to whether this is a good idea, in ordinary circumstances the answer is no. If the parish has such a consistent problem with overflow that it regularly needs to move some congregants to another building, then the parish needs to schedule another Mass on Sundays. The bishop can give permission for the parish priests to offer additional Masses on Sundays if there is a shortage of priests in the area. If the pastor is unwilling to consider adding an additional Mass to the schedule, concerned parishioners should approach the bishop for assistance.
