Is it permissible to perform the aqiqah for twins (a boy and a girl) with one calf or cow instead of three sheep, and if permissible, what are the required specifications?

The Sunnah is to sacrifice two sheep for a boy and one sheep for a girl as 'Aqiqah. The majority of scholars hold the view that sheep, camels, and cattle are all permissible for it. However, the closer opinion is that sharing in it is not valid, and this is the madhhab of the Malikis and Hanbalis. Sharing is not sufficient in 'Aqiqah because no sharing has been reported concerning it, and acts of worship are based on divine instruction, and because it is a ransom that cannot be divided.