I would have a chat to her teacher. Possibly your DD is playing with the kids at kinder but what sticks in her mind is the occasion when the other girls told her she couldn't play, so this is what she is reporting to you. The teacher should be aware of the activity occurring in the playground and may be able to allay your fears. If there is a social issue which the teacher is not aware of, speaking to her gives the opportunity to direct your DD and the other children in inclusive play. Whilst it is important for children to develop resilience, empathy and inclusiveness are just as important!