I think Reuven and Chaim might feel out of place at a U2 concert…if you had left the names as Adam and Larry, then it might work 🙂
I don’t have access to a Gemara right now, so I can’t look up the Rashi on Pesachim, but here’s my guess. The man’s parents each had children from previous marriages who later married each other. Thus, the couple are each his (half) siblings but they are halachically allowed to marry since they aren’t blood related to each other.