Non-PRO Japanese to English Art/Literary Cinema, Film, TV, Drama

Dear ProZ members,

I have a quick grammatical question about the following sentence. A middle school girl has been bullied by one of her classmates, and her mother is angry at her teacher who overlooked the situation.

今度いらっしゃる時は、学年主任の先生か校長先生か、どなたかと一緒にいらしていただけますか
(The next time you come, could you please bring one between the head of her year and the principal?)

Is this translation correct or should it be translated as "the head of her year, the principal or someone else"?

The first translation works better in the context, and the comma after 学年主任の先生か校長先生か seems to conferm it. However when you have Xか誰か the meaning is usually "X or someone else", so I'm a bit unsure.

Thank you so much!