Siman 478
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א אַחַר אֲפִיקוֹמָן אֵין לֶאֱכֹל שׁוּם דָּבָר. הַגָּה: וְלֹא יֹאכְלֶנּוּ בִּשְׁנֵי מְקוֹמוֹת, דְּלֹא עָדִיף מֵאִלּוּ הִפְסִיק בְּשֵׁנָה דְּאָסוּר מִשּׁוּם דְּהָוֵי כִּשְׁנֵי מְקוֹמוֹת (טוּר).
1 Not to eat after eating Afikomen. Containing two sections. After Afikomen, one should not eat anything. Rema: And he may not eat it in two places, because it is no better than if he interrupted sleep when it is forbidden to eat it because it is like two places (Tur).
ב מִי שֶׁיָּשַׁן בְּתוֹךְ הַסְעֻדָּה וְהֵקִיץ, אֵינוֹ חוֹזֵר לֶאֱכֹל. בְּנֵי חֲבוּרָה שֶׁיָּשְׁנוּ מִקְּצָתָן בְּתוֹךְ הַסְעֻדָּה, חוֹזְרִים וְאוֹכְלִים. נִרְדְּמוּ כֻּלָּם, וְנֵעוֹרוּ, לֹא יֹאכְלוּ. נִתְנַמְנְמוּ כֻּלָּם, יֹאכְלוּ. הַגָּה: וְכָל זֶה אֵינוֹ אֶלָּא שֶׁיָּשְׁנוּ לְאַחַר שֶׁהִתְחִילוּ לֶאֱכֹל הָאֲפִיקוֹמָן, אֲבָל שֵׁנָה קֹדֶם לָזֶה לֹא הָוֵי הֶפְסֵק (טוּר וְרַבֵּנוּ יְרוּחָ ם).
2 One who sleeps during the meal and wakes, does not return to eat. Members of a group, some of which slept during the meal, may return and eat. If they all slumbered and awoke, the may not eat. If all of them napped, they may eat. Rema: And all of this only applies where they slept after they began eating the Afikomen. But if they slept before that, it is not an interruption (Tur and Rabbeinu Yeruchem).