"Are you replying to us or to them?"
Translation:Odpowiadasz nam czy im?
If you ask an A/B question, you use 'czy'.
'albo' would suggest that the answer can easily be "Neither A nor B" or "Both A and B". Which is maybe not impossible, but doesn't seem very probable here. So frankly, on the level of being just a learner here, it's better to stick to using 'czy' in questions. You rarely mean something else.
thanks,would you tell me more about that? such as what is "to you,to me,..."? thanks so much