Pesachim 9:10-11

Pesachim 9:10

If the Passover offerings belonging to two groups got mixed up, each group takes one of the animals. A member of each group goes to the other group and each group says, “If this Passover offering is ours, withdraw from your group’s offering and join ours; if this Passover offering is yours, we withdraw from ours and join you in yours.” The same is true in the case of five groups of five members each, and of ten groups of ten members each: each group sends a member to every other group and they proceed in this manner.

Pesachim 9:11

If the Passover offerings belonging to two individuals got mixed up, each one takes one of the animals and designates some other person to join him in the offering. The owners of the sacrifices then say to the other’s guest, “If this Passover offering is mine, withdraw from your group and join mine; if this Passover offering is yours, I withdraw from mine and will join yours.”