Twins sleeping in the same room 6 months old

Our twins are almost 7 months old, 5 months adjusted age. Isabella acts more like a 7 month old and Georgio acts more like a 5 month old (He was IUGR). We cannot get them to go to sleep on their own in the same room separate cribs. They don't really bother each other much but once they have a bottle at night they all but fall asleep in our arms. Then we go lay them down and they wake up screaming. This is never exactly at the same time. They are formula fed (my milk dried up at around 4 months when I was really sick). Any advice?