Sholom,
About halfway down 151 Omud Aleph the Gemoro brings various "Maaseh Shehoyo's" to see what the Halochoh should be about a Shechiv Mera and Nachlos.
But what is bothering me is that the Simon in brackets before the Sugya "Shtim Nisht" because it starts with Zutra that's easy that's Rav Zutra Bar Tuvia,but then we have a story about "Imai DeRomi Bar Chomo" NOT in the Simon and then at the end of the Simon it brings 3 names and really it is only 2 people ie Rav Tuvi is the story of the sister of Rav Tuvi Bar Rav Masnoh and the last case is concerning Achsai DeRav Dimi BAR Yosef and in the Simon it is listed as VeRav Dimi VERAV YOSEF
I am not sure of the Yichus or Chashivus of Simonim in the Gemoro but something seems wrong here
Kol Tuv Boruch Kahan
1. The Hebrew Schotenstein edition cites the Dikdukei Sofrim who writes that the Girsa should be emended. He writes that it should read "Imei d'Zutra, Rami, Amram." (The advantage of this Girsa is that Rami (i.e. Rami bar Chama) is in the Siman, but I do not understand why "Imei" only appears in the Siman in connection with Rav Zutra and not also in connection with Rami bar Chama and Rav Amram.)
2. The Dikdukei Sofrim then cites some manuscripts which do not mention the Siman at all.
(I have no knowledge about Simanim in Shas, but it appears that they are not part of the Gemara itself but may have been inserted later.)
3. The Schotenstein edition also cites "Toldos Tana'im v'Amora'im" who writes that the first three in the Siman are as the Dikdukei Sofrim writes, and then he adds "from two sisters, Rav Tuvi and Rav Dimi bar Yosef." According to this, your question is answered because now the end of the Siman contains only two people. There is no independent Rav Yosef, but rather he is the father of Rav Dimi.
Kol Tuv,
Dovid Bloom