I think you'd have an even greater chance if you move them both alone. Because your two hens are broody, you can keep them together, but away from your flock. Do you have a dark or quiet place to keep them? We also have ten hens and three nesting boxes, but our girls chose favorite spots to lay and kick the broodies out.
I once tried to hatch a clutch with a broody, and at day 7, she was kicked out of that nest and took over a new one, so that when the hen left the first box with my eggs, my broody didn't need to return, having found a new nest to set. It was very disapointing.
If you have an area where they are kept near food and water but where the others cannot reach them, you'll do fine. Even if it's loud and bright, the hens will continue to set. Just keep them in their spots until it's dark and move them where you'll want them to set for the next 20 days. They'll wake up stress free and continue to try and hatch.
Some people hatch used a basement, although I'm not allowed to keep hens in the house.
So I put her in a nesting bucket in the feeding area seperated by a wall. She was able to hear the others up close and keep in contact with them. She was also able to leave when she willed, and go free-range for a few minutes, then return to set. Others keep their broodies in rabbit hutches. Whatever works, really. Do you have any place in mind?