יורה דעה פ״חYoreh De'ah 88

Se’if 1א׳

אֲפִלּוּ בְּשַׂר חַיָּה וָעוֹף, אָסוּר לְהַעֲלוֹת עַל שֻׁלְחָן שֶׁאוֹכֵל עָלָיו גְּבִינָה, שֶׁלֹּא יָבוֹא לְאָכְלָם יַחַד. אֲבָל בַּשֻּׁלְחָן שֶׁסֻדַּר עָלָיו הַתַּבְשִׁיל, מֻתָּר לִתֵּן זֶה בְּצַד זֶה.

Even with meat of a wild animal and a bird it is forbidden to put them on a table where one is eating cheese, so that he doesn't come to eat them together. But [to put] on a table that's meant for arranging cooked foods, it is permitted to put one next to the other.

Se’if 2ב׳

הָא דְּאָסוּר לְהַעֲלוֹתוֹ עַל הַשֻּׁלְחָן, דַּוְקָא בִּשְׁנֵי בְּנֵי אָדָם הַמַּכִּירִים זֶה אֶת זֶה, אֲפִלּוּ הֵם מַקְפִּידִים זֶה עַל זֶה; אֲבָל אַכְסְנָאִים, שֶׁאֵין מַכִּירִין זֶה אֶת זֶה, מֻתָּר. וַאֲפִלּוּ הַמַּכִּירִים, אִם עָשׂוּ שׁוּם הֶכֵּר, כְּגוֹן שֶׁכָּל אֶחָד אוֹכֵל עַל מַפָּה שֶׁלּוֹ, אוֹ אֲפִלּוּ אוֹכְלִים עַל מַפָּה אַחַת וְנוֹתְנִים בֵּינֵיהֶם פַּת לְהֶכֵּר, מֻתָּר. הַגָּה: וְדַוְקָא שֶׁאֵין אוֹכְלִין מִן הַפַּת הַמֻּנָּח בֵּינֵיהֶם לְהֶכֵּר, אֲבָל אִם אוֹכְלִין מִמֶּנּוּ, לֹא הָוֵי הֶכֵּר, דִּבְלָאו הָכֵי הַפַּת שֶׁאוֹכְלִין מִמֶּנּוּ מֻנָּח עַל הַשֻּׁלְחָן (אָרֹךְ וְהַגָּהוֹת אֲשֵׁרִ"י). אֲבָל אִם נָתְנוּ בֵּינֵיהֶם כְּלִי שֶׁשּׁוֹתִין מִמֶּנּוּ, וּבְלָאו הָכֵי אֵין דַּרְכּוֹ לִהְיוֹת עַל הַשֻּׁלְחָן, הָוֵי הֶכֵּר אַף עַל פִּי שֶׁשּׁוֹתִין מִן הַכְּלִי (בֵּית יוֹסֵף בְּא"ח סִימָן קע"ג). וְכָל שֶׁכֵּן אִם נָתְנוּ שָׁם מְנוֹרָה, אוֹ שְׁאָר דְּבָרִים שֶׁעַל הַשֻּׁלְחָן, דְּהָוֵי הֶכֵּר. וְיִהְיוּ זְהִירִים שֶׁלֹּא לִשְׁתּוֹת מִכְּלִי אֶחָד, מִשּׁוּם שֶׁהַמַּאֲכָל נִדְבָּק בַּכְּלִי (הַגָּ"ה אֲשֵׁרִ"י ואו"ה). וְכָל שֶׁכֵּן שֶׁלֹּא יֹאכְלוּ מִפַּת אַחַת. וְכֵן נוֹהֲגִין לְיַחֵד כְּלִי שֶׁל מֶלַח לְכָל אֶחָד בִּפְנֵי עַצְמוֹ, כִּי לִפְעָמִים טוֹבְלִים בְּמֶלַח וְנִשְׁאֲרוּ שִׁיוּרֵי מַאֲכָל בְּמֶלַח.

That which is forbidden to put together on the same table, that is precisely only with two men who recognize each other, even if they insist on not sharing food with each other. However, by guests who don't recognize one another, it is permitted. And even by those who recognize each other, if they make any sign, such as if each one eats on his own tablecloth, or even if they eat on a single tablecloth but they place bread between themselves as a sign, it is permitted. Rema: And this is precisely if they don't eat from the bread that's placed between them as a sign, but if they eat from it, it is no longer considered a sign, because even without this purpose, bread from which they eat from is placed on the table. But if they placed a drinking vessel between themselves, and if not for this purpose it is not normal for it to be on the table, it would be a sign even if they drink from the vessel. And of course if they place on [the table] a candelabra or other items on the table that they are [valid] signs. And they should be careful not to drink from a single vessel because food sticks to the vessel. And of course they should not eat from the same bread. And so is our custom to have individual salt-vessels for each person themselves, because sometimes when they dip into the salt there remains leftovers of the food in the salt.