We only said this halakha in a case where those members of the previous groups did not include them in the zimmun in their original place, but in a case where they included them in the zimmun in their original place, their obligation to participate in a zimmun has left them. The obligation incumbent upon these three individuals to form a zimmun stems from their obligation to form a zimmun with the members of their original groups. If their groups already included them in a zimmun, their obligation as individuals has lapsed and they can no longer form another zimmun.

In order to explain the general principle contained in this halakhic ruling, Rava said: From where do I derive to say this halakha? As we learned in a mishna: A ritually impure bed, half of which was stolen or half of which was lost, or it was divided by brothers after they inherited it from their father, or was divided by partners, it is ritually pure. This is true with regard to any ritually impure utensil that was broken or divided; it is no longer a utensil and is therefore ritually pure. However, if they restored it and reattached the parts, it is susceptible to ritual impurity from here on.

Rava infers: From here on, yes, it is susceptible to ritual impurity, retroactively, no, it does not reassume its previous status of ritual impurity. Apparently, once they divided it, the ritual impurity left it. Although it was restored, it does not reassume its previous status of ritual impurity. Here, too, once they included them in the zimmun, their obligation left them and they do not reassume their previous obligation.

The mishna explained the circumstances in which two groups that were eating in one house may combine to form a zimmun. The Gemara adds: It was taught: If there is a common waiter among them, serving both groups, the waiter joins them into a single group, even if they cannot see each other.

In the mishna, we learned: One does not recite a blessing over wine until he adds water to it, that is the statement of Rabbi Eliezer. And the Rabbis say: One recites a blessing over it. Regarding this, the Sages taught in the Tosefta: Over wine, until he added water to it, one does not recite: Who creates fruit of the vine; rather, he recites: Who creates fruit of the tree, as it is merely fruit juice and not wine. Moreover, since it is not halakhically considered wine, one ritually washes his hands with it. Once he added water to it, however, it is considered wine, and one recites over it: Who creates fruit of the vine, and one does not ritually wash his hands with it, that is the statement of Rabbi Eliezer. The Rabbis say: In either case, whether water has been added or not, it is considered wine for all intents and purposes, and one recites over it: Who creates fruit of the vine, and one may not ritually wash his hands from it.

In accordance with whose opinion is that halakha which Shmuel said: A person may perform all his needs with bread? He may use it for purposes other than food, and he need not be concerned that he is treating the food contemptuously. In accordance with whose opinion among the tannaitic opinions cited above? The Gemara answers: It is in accordance with the opinion of Rabbi Eliezer, who permits one to wash his hands with undiluted wine.

Rabbi Yosei bar Rabbi Ḥanina said: The Rabbis agree with Rabbi Eliezer with regard to a cup of blessing, e.g., the cup of wine over which Grace after Meals is recited, that one does not recite a blessing over it until he adds water to it. What is the reason? Rav Oshaya said: We require that a mitzva be performed in the best possible manner.

With regard the issue of wine itself, the Gemara asks: And according to the Rabbis, for what is undiluted wine, which is virtually undrinkable, fit? Rabbi Zeira said: It is good for koraiytei, a medicinal drink made of wine and oil.

The Gemara continues to discuss the topic of using food. The Sages taught: Four things were said with regard to bread: One may not place raw meat on bread so the blood will not drip onto the bread and render it inedible; and one may not pass a full cup of wine over bread lest the wine drip on it and ruin the bread; and one may not throw bread; and one may not prop up a dish with a piece of bread. The basis for these laws is the need to treat bread with respect.

The Gemara recounts: Ameimar, Mar Zutra and Rav Ashi ate bread together when they brought dates and pomegranates before them. Mar Zutra took fruit and threw a portion before Rav Ashi. Rav Ashi was astounded and said to him: Does the Master not hold with that which was taught in a baraita: One may not throw food? He responded: That was taught with regard to bread, not other foods. Rav Ashi challenged him again: Wasn’t it taught in a baraita: Just as one may not throw bread, so too one may not throw other foods? Mar Zutra said to him: Wasn’t the opposite taught in another baraita: Although one may not throw bread, he may throw other foods?

Rather, that is not difficult, as the two baraitot address two different cases. This baraita, in which it is taught that one may not throw other foods, refers to a food item that becomes disgusting when thrown, whereas that baraita, in which it is taught that one may throw other foods, refers to a food item that does not become disgusting when thrown.

Similarly, the Sages taught: One may draw wine through pipes before a bride and groom as a blessed omen, and one may throw roasted grain and nuts before them in the summer, but not in the rainy season, as in the summer they can be retrieved and eaten, which is not the case in the rainy season. But one may not throw cakes, neither in the summer nor in the rainy season.

Rav Yehuda said: If one forgot and put food items in his mouth without reciting a blessing, he moves them to one side of his mouth and recites the blessing.

The Gemara notes that there are three baraitot on this topic: It was taught in one baraita: He swallows them. It was taught in another baraita: He spits them out. Another baraita taught: He moves them to the side of his mouth.

The Gemara explains: That is not difficult, as each baraita addresses a different case. This baraita in which it was taught: He swallows them refers to liquids, as there is no alternative. This baraita in which it was taught: He spits them out, refers to a food item that does not become disgusting and if he removes it from his mouth he can subsequently eat it. This baraita in which it was taught: He moves them to the side of his mouth, refers to a food item that becomes disgusting, in which case it is sufficient to move it to the side.