(Mishnah): If Reuven was a partner with each of Shimon and Levi (his neighbors in the Mavoy) in wine, they need not be Me'arev;

If he was a partner with one in wine and with one in oil, they must be Me'arev;

R. Shimon says, in either case they need not be Me'arev.

(Gemara - R. Ba citing R. Yehudah): Our Mishnah teaches a typical case. If he was a partner with this one in wine and with this one in wine, since he is not adamant if they get mixed, he need not be Me'arev;

If he was a partner with this one in wine and with this one in oil, since he is adamant if they get mixed, he must be Me'arev.

(R. Ba bar Kahana citing R. Chiya bar Ashi citing Rav): Our Mishnah discusses when they are put in one Kli. (If they are in two Kelim, even wine and wine, he must be Me'arev.)

(R. Zerikan): R. Shimon holds that it is normal to drink Anigron (wine and oil mixed with water in which beets were cooked. Therefore, they are proper to join, even if they are in two Kelim.)

(Beraisa - R. Elazar ben Tadai): In both cases they are forbidden until they are Me'arev.

(R. Acha citing Rav): The Halachah follows R. Elazar ben Tadai.

(R. Yakov bar Acha citing R. Ze'ira): R. Elazar ben Tadai holds like R. Meir.

Question: Like which teaching of R. Meir does he hold?

Answer #1 (R. Mana): R. Meir said that [Chatzeros that open to a Mavuy must join] through Eruv [Chatzeros] and through Shituf [Mavo'os. He requires both, lest the law of Eruv be forgotten. Also here, one may not rely on partnership of wine for this reason.]

Answer #2 (R. Yosi bei R. Bun): R. Meir said that we are Me'arev for someone only with his knowledge. (The partners did not know that the wine will serve like an Eruv.)

According to R. Mana, according to R. Ze'ira (who said that R. Elazar ben Tadai holds like R. Meir), Rav (who rules like R. Elazar ben Tadai) holds like R. Meir [who requires Eruv Chatzeros and Shituf. We explained this like YERUSHALMI KI'PESHUTO.]

(R. Ze'ira citing R. Yochanan): Regarding Eruvin (when there is already Shituf) and Ta'anis Tzibur, everyone conducts like R. Meir (there is Birkas Kohanim at Minchah and Ne'ilah of Ta'anesim).

(R. Yakov bar Acha citing R. Yochanan): Also regarding Megilas Esther, everyone conducts like R. Meir [who obligates reading all of it].