Think of two circular disks, one is the "objective-self" and the other is the "subjective-self." Ideally, the latter covers the former exactly.
Your daughter's s-disk is much smaller than her o-disk; her objective-self is not fully covered by her subjective-self. Part of her objective-self is exposed and vulnerable.
The other girl's s-disk is much larger than her o-disk; her subjective-self, while may not fully cover her o-disk, encroaches onto those whose o-disk is exposed, like your daughter's.
The other girl may see others as an extention of herself, subject to her control and manipulation.
Your daughter may look for herself in others' reaction to her, having others cover part of her o-disk.
Both have boundary issues, your daughter's needs to be pushed outward, and the other girl's needs to be shrunk.
It's never too early to talk about "self and boundary" or "Personal Boundary" to a child. Google the terms.
(If they were adults, the other girl is the narcissist. Your daughter is a victim of narcissistic rage. The other girls are called "flying monkeys.")
