The way your post reads is that you are wanting a closed adoption. Are you sure that you don't even want a semi-open where you could receive pictures and card updates a couple times a year, your children don't have to know that it is their sibling but then you could know that you found the right parents.
If you ever need to chat just PM me. We are looking to adopt but I am here to learn as much as I can!!!
Kimberly