You're going to have to check with the exotic vets local to your area, but I would assume the after everyting said and done (surgery, pre- and post- op vet appointments, meds) you could be looking at about $200-$250 per rabbit.
Vet costs vary widely from one part of the country to another, and even within the same city. I once had estimates for stone removal surgery for a guinea pig that ranged from $400 to $2400.