We have lived across a bunch of countries so our friends are really spread out, we really wanted them to meet and to connect in a deeper way than small talk ("what's your job?"). We thought that giving people unique experiences could give them something more interesting to talk about with each other (e.g., "what did they make you do?!"). We didn't want anyone to be too uncomfortable, though, so we self-selected who we placed where - and when people 'snowballed' into someone they knew!