This might sound strange, but I had the exact same situation while I was in nursery/preschool. In my case it was a boy, but other than that, pretty much the same thing happened every day.
My little brother was an infant at the time, and both my parents around 26-27, this may be the reason why my cries for help were completely ignored. To put this into context, it was Central Europe in the early 90s, views about raising children were completely different, especially from Western standards, let alone modern Western standards. We were 'left on our own' very often, there are many situations where for my own child I would run to the teacher, parent, council, psychologist, whatever, but back then I was just told to get over it.
Anyway, that is how it was and I am absolutely not blaming anyone for it. However, I must tell you, that little boy harassing me in school gave me anxieties I couldn't get rid off for many, many years. It may seem like a small thing (maybe not for you as you are seeking for help), But children are in an incredibly vulnerable position at your daughter’s age, with overwhelming emotions. I think you must do something. Some of the things that comes to mind: Have you tried to speak to the teachers? Have you tried to speak to the girl’s parents? (before you do either of these, I would ask for your daughter’s permission though). This doesn’t sound like bullying I know, but it is.