It was really chill for the cashier position! It was a bunch of high schoolers and a few adults so it was really laid back (I’m a college sophomore). But I assume for internship and corporate job group interviews it’ll be more tense. No matter what the atmosphere, I would still tell the hiring manager you stutter, and if everyone in the group heard about it they know as well. So whether they choose to judge beyond that is no longer on you but them. I would practice will online interview tools like hirevue and quincia or anything else that’s free. I personally hated using it cause I have to see myself stutter and I hate it. But if you have no one else to practice with I would use those tools!