I like the idea of having a meeting with the other parents, if only to see how the admin reacts to the idea. Meaning, are they interested in facilitating a resolution to the issue, are they interested in the safety of the other child, or would they like just to keep gossiping about the other family? I'd not be comfortable staying in a school situation where the admin is willing to gossip about any child or family, even if they have been a "thorn in the school's side." I realize this is level 101, but anyone willing to gossip about that family is willing to gossip about yours. Is that where you want to be?