If
one has two groups of daughters from two wives, and he says: “I gave my
eldest daughter in betrothal to a certain man, but I do not know if it
was the eldest daughter of the older ones, or eldest of the younger
ones, or the youngest of the older ones - they are all prohibited to
marry other men, except for the youngest daughter of the younger ones –
says Rabbi Meir.
Rabbi Yosi says that they are all permitted to
marry other men, except for the eldest of the older ones, for a man
would not voluntarily put himself in a position of doubt.