Eruvin7: 6
כֵּיצַד מִשְׁתַּתְּפִין בְּמָבוֹי? מֵנִיחַ אֶת הֶחָבִית וְאוֹמֵר, ,,הֲרֵי זוֹ לְכָל בְּנֵי מָבוֹי.“ וּמְזַכֶּה לָהֶן עַל יְדֵי בְנוֹ וּבִתּוֹ הַגְּדוֹלִים, וְעַל יְדֵי עַבְדּוֹ וְשִׁפְחָתוֹ הָעִבְרִים, וְעַל יְדֵי אִשְׁתּוֹ. אֲבָל אֵינוֹ מְזַכֶּה לֹא עַל יְדֵי בְנוֹ וּבִתּוֹ הַקְּטַנִּים, וְלֹא עַל יְדֵי עַבְדּוֹ וְשִׁפְחָתוֹ הַכְּנַעֲנִים, מִפְּנֵי שֶׁיָּדָן כְּיָדוֹ.
How do we make a shituf for an alley? One places a barrel and declares, ‘‘Let this belong to all the residents of the alley.’’ He may confer possession to them through his adult son or daughter, through his Jewish manservant or maidservant, or through his wife. But he may not confer possession through his minor son or daughter, nor through his Canaanite slave or slavewoman, because their hand is like his hand.
Eruvin7: 7
נִתְמַעֵט הָאֹכֶל, מוֹסִיף וּמְזַכֶּה, וְאֵין צָרִיךְ לְהוֹדִיעַ. נִתּוֹסְפוּ עֲלֵיהֶם, מוֹסִיף וּמְזַכֶּה, וְצָרִיךְ לְהוֹדִיעַ.
If the food became diminished, one may add and confer possession, but he does not have to notify [them]. If more [residents] were added, he may add and confer possession, or he must notify [them].