Parashas Bo · Shemos 12:7 · TT note 4
Torah Temimah on Shemos 12:7, note 4 (on עַל הַבָּתִּים אֲשֶׁר יֹאכְלוּ) points to Pesachim 86a.
Sefaria — Exodus 12:7
Sefaria — Torah Temimah on Exodus 12:7
Sefaria — Pesachim 86a
E-Daf — Pesachim 86a
English: It was taught: “On the houses in which they shall eat it” — this teaches that the Pesach may be eaten in two groups. One might think that a single eater may eat in two places — therefore it says: “It shall be eaten in one house.”
Derash allowing two groups from one Pesach while restricting one person from moving between places.
Those enrolled on one Pesach may eat as two separate groups, but an individual may not switch locations mid-meal.