my daughter wont share to others

I never specifically had this problem. But for breaking most habits I have to go back and reverse whatever I taught or they watched. And practice what I preach. We have to remember that kids learn by what they see, hear and repitition. In your case at some point you probally made it clear that she should always share with her brother. Well that part it seems that she mastered. So now you have to teach her that its very important that she shares with everybody...and soon you will have to teach her that "everybody" doesn't mean strangers. LOL. Parenting is a lifelong teachers position. Hope you like your career choice