Sister as nanny while I work in China

I have a quick question. Both my wife and I plan on teaching English in Shanghai for a year. My sister currently lives with us and helps us take care of our baby in exchange for a free place to live and an allowance for food and necessities. Would it be possible to continue this arrangement in Shanghai? In other words, we would like her to live with us in Shanghai and take care of our baby while we are at work. We would be paying for all of her expenses during the year. Would she be able to do this in an F type? We saw the S2 visa but we would like her to stay longer than the S2 type allows. Thank you for your time and information.