Siman 200

Our teacher, the Beit Yosef, wrote: Three who ate as one, one must interrupt against his will for the two and answer with them the blessing of zimun. And even if he did not want to interrupt—they perform zimun upon him whether he answers or does not answer, as long as he is standing there. But two are not obligated to interrupt for one. And therefore, the obligation of zimun does not take effect until they agree to interrupt for the one and bless. And if they did not want to interrupt, and he performed zimun upon them—he has done nothing. And if they did not want to interrupt—even he is not permitted to bless and go out to the market until the two finish and he performs zimun upon them; for he has already become obligated in zimun, and how can he bless without zimun? Thus far his words.

And in his great book he ruled that if the matter is urgent for the individual to go—he may recite the blessing and go. This is because the Rashba wrote in the name of Rav Hai Gaon that the individual does not need to wait for the two, and he may recite the blessing alone. For the obligation of zimun is only at the conclusion of their eating, and as long as the two have not finished their meal—the obligation of zimun does not apply to them, and the individual may recite the blessing for himself. And that which was explained in siman 193, that the individual is not permitted to separate, that is when all of them have finished their meal and wish to separate. But as long as they have not finished the meal—he is permitted to recite the blessing by himself. And so ruled the great Acharonim (Bach, and Magen Avraham subsection 2, and Eliyah Rabbah subsection 3 in the name of the Ra'avyah, see there). And it is certain that without need one should not do so. However, if it is urgent for his business or some other need—he may do so (Eliyah Rabbah ibid.). And there is one who distinguishes: that if they began to eat together—it is forbidden for him to recite the blessing alone. And if they did not begin to eat together—it is permitted (Taz subsection 1). And we have already written there in section 14 that this reasoning is not agreed upon, see there.

Until where must the individual pause for the two? There is a dispute in the Gemara (46a): One says until the zimun blessing, meaning: since the one leading the blessing returns and says "Blessed is He of whose food we have eaten and through whose goodness we live" – he returns to his eating, for this is the essence of the zimun blessing which the individual does not say. And one says: until they finish "Who feeds all." And the reason: because in the zimun blessing there is no Name and Sovereignty, and therefore without the blessing of "Who feeds" it does not appear as a blessing (Tosafot ibid.). The poskim also disagreed regarding this. Our teacher, the Beit Yosef, ruled until the zimun blessing, and our teacher, the Rema, ruled until "Who feeds all." And such is the common custom, and one should not change it. And thus ruled the Bahag.

One who paused for the two—he returns and eats without a blessing, for it was his intention to eat more. But if in truth it was not his intention to eat more, and he changes his mind and eats—he requires a blessing at the beginning (Magen Avraham, subsection 5). And when he finishes his eating and blesses, he shall begin from the blessing of "HaZan." Even when he paused for them until the conclusion of the blessing of "HaZan," he returns and blesses it, for granted that he was exempted through his hearing for what he ate before they blessed, but for what he ate afterward he was not exempted. And even if he did not eat afterward—he requires the blessing, for he did not intend to be exempted from it through his hearing. But if in truth he intended not to eat more, and to be exempted through his hearing—he begins afterward from "Nodeh Lecha."

If one paused for two, and afterward two others came and ate with him—he joins with them for zimmun. And we do not say that he already fulfilled his obligation of zimmun when he paused for the previous two, for since two others have now joined with him—he returns to his obligation (Bach and Magen Avraham subsection 3). And it appears to me that this is specifically when he ate after he paused for the two. But if he did not eat—he no longer joins. And all the more so in a group of five or six or more, where they paused for three of them or more, that they should not bless afterward with zimmun even if they ate afterward, for the obligation of zimmun has already departed from them after they all paused for those blessing. But if there was a group of nine, and one paused for the two who were blessing—he can join afterward with two others, and afterward with two others; since only he paused and they remained in their obligation—he joins with them. And if there was a group of five people, and one paused for two—he cannot join further with the remaining two, for an obligation of zimmun did not remain among them (Magen Avraham subsection 3). However, if they all ate afterward—they are obligated to perform zimmun for what they ate afterward (and so it is implied from the Gra"z). And it is not similar to what we wrote that even if they ate afterward they do not perform zimmun, for that is when they all paused for those blessing. But not when only one paused, and they have not yet fulfilled the obligation of zimmun; therefore, even though only two remained, nevertheless when they all eat afterward, he joins their obligation. Thus it appears in my humble opinion regarding these laws. (The Even HaEzer disagrees with the Magen Avraham. and according to what I have written there is no disagreement. Examine carefully and you will find it easy.)

The Tur wrote that if they are ten, and three interrupt for seven—they only need to interrupt until they have said "Blessed is our G-d." And if the three returned and ate—they can perform zimun together. Thus far his words. That is to say: even if one who interrupts for two must wait until "Who feeds all," this is because without him there is no zimun. However, three who interrupt for seven, behold even without them there is a zimun, and their interruption is only for the sake of the mention of the Name. Therefore, they only need to interrupt until they have said "our G-d." And therefore, when they returned and ate, they can perform zimun together. And it is not called "the zimun has departed from them" like in the previous law, for behold they did not interrupt for the sake of the zimun but rather for the sake of the mention of the Name. And they can also join with seven others for the mention of the Name, for regarding this "the zimun has departed from them" is not applicable, as wherever ten eat the Divine Presence dwells (Magen Avraham, end of subsection 3).