Thanks for the feedback, now I'll tell you what I did and please tell me if it was appropriate or not and how to proceed from here.
After it was apparent that this behavior was going to continue, I attempted to redirect the child's focus onto a solitary activity (coloring). The behavior continued, so I figured she must have a need that wasn't being met so I went and talked to my kids to see if she was possibly feeling excluded. I arranged for a group activity that they could enjoy together. She didn't want to participate and they left soon after.
This is my best friend so I can't just not have them over. My mother thinks I should talk to my friend about it (my kids were beginning to copy the behaviors, but I nipped it in the bud), but I feel that in doing so would likely not go over well and be a friendship ender which is not at all what I want.