Pesachim 87A

מתני׳ האשה בזמן שהיא בבית בעלה, שחט עליה בעלה ושחט עליה אביה ⁠— תאכל משל בעלה. הלכה רגל ראשון לעשות בבית אביה, שחט עליה אביה ושחט עליה בעלה ⁠— תאכל במקום שהיא רוצה.

Mishnah: A woman, when she is living in her husband’s house, if her husband slaughtered the Paschal lamb on her behalf and her father also slaughtered the Paschal lamb on her behalf, she should eat from her husband’s lamb because it is assumed that the wife intended to be included in her husband’s group. However, if, as was often customary, she went on the first Festival following her marriage to observe the Festival in her father’s house, then, if both her husband slaughtered the Paschal lamb on her behalf and her father also slaughtered the Paschal lamb on her behalf, she may eat in whichever place she wishes, since it is not obvious with whose group she intended to be included.

יתום ששחטו עליו אפוטרופסין ⁠— יאכל במקום שהוא רוצה. עבד של שני שותפין לא יאכל משל שניהן. מי שחציו עבד וחציו בן חורין לא יאכל משל רבו.

In the case of an orphan with multiple guardians, if each of his guardians [apotropsin] slaughtered a Paschal lamb on his behalf, intending that he be included in their group, he may eat in whichever place he wishes. A slave jointly owned by two partners may not eat from the lamb of either of them, unless it was stipulated beforehand from whose lamb he will partake. One who is half slave and half free man may not eat from his master’s lamb. It is assumed that the master did not intend to allow this person’s free half to partake of the lamb, and therefore the master did not slaughter the lamb with him in mind. Consequently, the half slave is not included among those registered for his master’s offering unless he was explicitly included.