How do you approach girls in groups?

Let's say you see girl A. But she is in a group. How do you approach this situation (pun intended).

For starters, I know that if I don't focus on the girl, she thinks I'm not interested. I also know if I make eye contact with the girl, I shouldn't break circle first. But then what do I do with other people? Especially the other males?

Even my pre-school teacher noted for me to be confused in highly varied group situations, so this one's especially challenging for me. But I believe I can work it out with some good guidance.