The dogs are still moving around freely and they haven't started coughing yet maybe that was unwise but a bit late now.
Cross-species transmission of viruses is rare. I have no idea how likely it is for the dogs to spread the virus to surfaces in the rest of the house by going into the rooms where the sick are and going to other places after that. It may be the safe bet to keep the dogs away from the sick.
All you can do is keep the sick confined to their rooms and take meticulous care of hygiene when caring for them.