One of the ways I organize and plan for interviews is to use an interview matrix. I take the essential skills from the job analysis and use them in the interview matrix to decide who will ask which questions. No, I don't make those decisions—I ask the interviewers who wants to ask which questions. Now the interviewers know what kinds of questions to develop, and where to expect the interview to start.
Here's what the interview matrix looks like:
|Interviewer/Area||Sally||Sam||Stan||Tom||Tina||Everyone meet to eval candidate|
|Ability to learn system quickly||X||X|
Everyone has a chance to ask different questions about two different areas, leading to different conversations. Because two people ask questions about the same area, you get overlap, but not the same conversation. When Sally and Tom ask about problem-solving, they both ask about it, but with a different focus, because their other areas are different.
The everyone column on the right is for everyone to meet at the end of the interview to share their ideas about the candidate.
I suspect you're already doing something like this, but if not, make it explicit. You can even provide the candidate a copy of this sheet—at least the upper part with the people and the times, so the candidate remembers who he or she spoke with when.