Do these moms work? If not, could they be organized into a co-op? You could be the "main" teacher, but they all could help in some way. Instead of every day, meet only two or three days. They would be responsible for their child's education on the "off" days. Then you wouldn't have to worry about the legalities of it, because they would still be homeschooling themselves.
I agree with Jackie. If they are looking at hsing, then you would want to encourage them to be the main teacher of their children. You could act as their consultant and help them with questions that arise. Then just plan on getting together for some group things like art, music and pe. That would be hsing. If you're looking to earn an income, you'll be starting a private school instead.
Thanks for all the ideas! One of the parents works, the other does not want to homeschool themselves, but loves the idea of hsing. Not sure on the others views, but that is an idea.