I don’t have any personal experience with it, but when I was in Guatemala, I became friends with another American who was there adopting her son, and she was able to do it to some extent. I remember she also had a tube she used to provide supplemental nutrition.
It’s something you’ll want to talk to the future expectant mother you eventually match with. I’ve read that some birth mothers are not at all comfortable with adoptive breastfeeding, feeling that it usurps one of the few things that only they can do for the baby.