Feeding three at a time is something that calls for a bit of skill and imagination - or some assistance from an engineer.
We've two sets of the so called Podee bottles. These combine a bottle and flexible tubes. The movement the baby makes on the nibble causes suction that pulls milk from the bottle through the tubes. This way the baby can drink without anyone holding the bottle. :)
It works great when the baby has gotten familiar to the nibble. Filip is a pro, Oscar is learning and Elin still prefer the regular bottles.