I'm not an expert, but it sounds like a viable plan.
Have separate shoes and smocks for visiting the two groups and tend the new birds first every time. :)
A sick animal should NEVER be sold or given to someone else. That might have been how she got into this position -- by someone being irresponsible and pushing off a sick animal onto someone who didn't know any better. :mad:
I think that this is important if you can manage to do it.
If you ever intend to sell chicks/birds you need to know what this disease is so that you are not the cause of someone else's flock being infected. :)