Amazon group interview in Santa Monica?

I got connected with a recruiter in Amazon. Backend java systems. They want to interview me but say I have to go to Santa Monica for a group interview. Not group together, but with multiple interviewers and multiple interviewees so they can cycle through us not wasting any time. I’ve never had this in my 10YOE. They also said if I don’t fly down there next week when they are doing this, then I have to just wait until next time, still in SM. I thought I would be applying locally to Palo Alto office or wherever the local San Francisco team is located. Anyone in the Bay Area interview with amazon and have a similar or different experience? Is this common/required?