אורח חיים קע״דOrach Chayim 174

Se’if 4ד׳

אִם קָבַע לִשְׁתּוֹת לִפְנֵי הַמָּזוֹן, אֵינוֹ צָרִיךְ לְבָרֵךְ עַל יַיִן שֶׁבְּתוֹךְ הַמָּזוֹן, דְּיַיִן שֶׁלִּפְנֵי הַמָּזוֹן פּוֹטְרוֹ; וְכֵן יַיִן שֶׁל קִדּוּשׁ פּוֹטֵר יַיִן שֶׁבְּתוֹךְ הַמָּזוֹן; וְכֵן הַמַּבְדִּיל עַל הַשֻּׁלְחָן, פּוֹטֵר הַיַּיִן שֶׁבְּתוֹךְ הַמָּזוֹן וְיֵשׁ אוֹמְרִים שֶׁאֵין בִּרְכַּת יֵין הַבְדָּלָה פּוֹטֵר, אֶלָּא אִם כֵּן נָטַל יָדָיו קֹדֶם הַבְדָּלָה, הִלְכָּךְ הַמַּבְדִּיל קֹדֶם נְטִילָה יְכַוֵּן שֶׁלֹּא לְהוֹצִיא יַיִן (וְע"ל סי' רצ"ט סָעִיף ז') שֶׁבְּתוֹךְ הַסְעֻדָּה; וּבְדִיעֲבַד שֶׁלֹּא כִּוֵּן כָּךְ, פּוֹטֵר יַיִן שֶׁבְּתוֹךְ הַסְעֻדָּה, דִּסְפֵק בְּרָכוֹת דְּרַבָּנָן לְהָקֵל.

If he fixed himself to drink before the meal, he need not bless over the wine within the meal, for the wine before the meal exempts it; and likewise the wine of kiddush exempts the wine within the meal; and likewise one who makes havdalah at the table exempts the wine within the meal. And there are those who say that the blessing over the wine of havdalah does not exempt unless he washed his hands before havdalah; therefore one who makes havdalah before washing should intend not to exempt the wine (and see below, siman 299, se'if 7) that is within the meal; and after the fact, if he did not so intend, it exempts the wine within the meal, for a doubt in blessings, which are rabbinic, is resolved leniently.

Se’if 5ה׳

כָּל מַה שֶּׁשּׁוֹתֶה בְּתוֹךְ הַסְעֻדָּה דַּי לוֹ בִּבְרָכָה אַחַת, אֶלָּא אִם כֵּן כְּשֶׁבֵּרַךְ לֹא הָיָה דַּעְתּוֹ לִשְׁתּוֹת אֶלָּא אוֹתוֹ הַכּוֹס וְנִמְלַךְ לִשְׁתּוֹת אַחֵר. הַגָּה: וְכֵן מִי שֶׁבָּא לִסְעֻדָּה וּמוֹשִׁיטִין לוֹ הַרְבֵּה כּוֹסוֹת, מְבָרֵךְ עַל כָּל אֶחָד וְאֶחָד דְּהָוֵי נִמְלָךְ (כָּל בּוֹ) וְע"ל סי' קע"ט; וְכֵן מִי שֶׁבֵּרַךְ עַל כּוֹס בִּרְכַּת נִשּׂוּאִין וְאֵינוֹ יוֹדֵעַ לְהֵיכָן יַגִּיעַ הַכּוֹס, כָּל אֶחָד צָרִיךְ לְבָרֵךְ, דְּמִקְרֵי נִמְלָךְ (אֲגֻדָּה פֶּרֶק עַרְבֵי פְּסָחִים) וְע"ל סִימָן ק"צ.

Whatever he drinks within the meal, one blessing is enough for him, unless, when he blessed, his mind was to drink only that cup, and he changed his mind to drink another. Hagah [Rema]: And likewise one who comes to a meal and they hand him many cups blesses over each and every one, since this counts as changing his mind (Kol Bo); and see below, siman 179. And likewise one who blessed over the cup of the wedding blessing and does not know where the cup will reach — each one must bless, since it is called changing one's mind (Agudah, chapter "On the eves of Passover"); and see below, siman 190.