What are strategies for handling multiple students visiting office hours?
I would suggest an alternative: rotate after each question, not after each student. So solve a question from one student, then allow a different student to ask a different question. If multiple classes are present, you can go by class rather than by student.

This has several advantages:


Everyone will prioritize their questions: no one feels rushed by the people behind them, nor like they wasted a trip because of someone in front of them
Students (in the same class) may not all have the same questions, but they'll benefit from seeing how you approach each problem.
Students in different classes can digest your previous answers and try to apply those concepts to new questions while they wait for you to circle back
This should be helpful for the majority of students -- if there are any special cases (e.g., students with individual issues that aren't useful to the rest of the group), they'll see what's going on and will appreciate your invitation to schedule an appointment
You get to keep your position at the whiteboard, which is less exhausting for you