How do I ask someone out in a group setting?

So I'm in an meetup group for gaming (board games/video games) and we meet once a week, but sometimes we do other stuff normally once a month, like we went to a fair over the weekend.

While at the fair, we kind of went into an unofficial buddy system and I was hanging out with one of the girls in the group, and while we were hanging out with the entire group of us who went there, we were sticking close to each other the entire time.

While we were hanging out together, it was a lot of fun. I got to know her some more directly and we have a lot in common. Because of this, i want to ask her out on a date.

The thing is, we don't often get the chance to be truly alone. Oftentimes there are other people in the group there, so oftentimes I don't think I would get the chance to ask her out directly.

Also I'm a little worried on what would happen if she says no. Will she feel uncomfortable being there or being around me? I certainly don't want her to feel uncomfortable.