My DH, a physician, is considering joining a new group practice, and they've set up a meet-and-greet dinner that I'm also invited to. What should I wear???

Dinner is at a restaurant that is casually upscale -- the kind of place I'd expect to see people go for a business lunch, but I'd go dressed causally (jeans, casual top) if I was just going for dinner with my family. We'll be having dinner with a few other physicians, as well as the administrative team (local administrator, HR recruiter, COO, potentially a few others) who are coming in from a city a few hours away where the practice is based. I've been a SAHM for the past 7 years and I don't think I've dressed for any sort of "business" occasion a single time since then! Obviously this dinner is about my DH, not me, but I still want to dress the right way! Any/all suggestions are appreciated - TIA!