Yes. It is very easy to incorporate an older child into the ceremony, or have a ceremony for twins, triplets, quads etc. In Australia, we can also hold ceremonies for two families who have come together to celebrate. For example two brothers and their wives, had one child each who were the same age. We held a ceremony that honoured the role of family and friends, and we focused a part of the ceremony on each child and their parents, acknowledging their love and commitment to the individual, and named the child. However in some countries, this is not the case. Please check with your celebrant.