How much skin can a muslim girls how infront of another women?

The Hanafi position is that you wear hijab in front of non-Muslim women as well. But some say that you can follow regular clothes like with family. In which case, it's from the navel to knee (as a woman). Not saying you can go topless, that's immodest, but this rule is because sometimes it would be completely necessary for a woman to breastfeed her child and there's no private foom to do so.