This reminds me of the first job I interviewed for (non-academic). I met with over 10 people all from different departments, performing different functions within the company. Although most of the departments had nothing to do with me and I wouldn't be working in or with them, it was still necessary to show that I was suited to the organization's overall goals and culture - aspects that cross disciplinary boundaries. I imagine that in the course of your career, you'll be faced with this type of situation again. So like @TakeruK said, it's important to be able to show at least a minimal amount of interest and knowledge even in topics you may not ever work on because, I think, it shows that you care about the organization as a whole and if needed, you can contribute in fields that may not be in your comfort zone. Also, it's important to learn how to discuss your interests with someone that may not be in your specific research area - more often than not, whether it's submitting papers for publication, applying for a job or a grant, giving conference presentations, you won't be preaching to the choir. So yeah, the interviewers whom you're not all that thrilled about may be thinking the exact same thing about you. So in addition to preparing to express interest in them, you'll need to be able to discuss your plans in a way that can keep them from falling asleep.
This isn't easy, even as a grad student, department dinners were always full of people trying to show interest / gain interest in stuff that's unrelated. Like me, trying to explain my research on race relations to a person researching Renaissance tragedies while also trying to be polite and show sincere interest about that person's research on Hamlet and other stuff.... So yeah, as long as we're in academia, this will be a recurring situation.