10K per family, you cannot give money to family members, it still counts to the total. Now a group of friends that's different carrying split money is different, each one is entitled to US$10,000 on it's own.
Only if each one declares it...or carry less than 10k (even if it's just a few bucks). In addition if it's apparent they're together the government could very easily go over that fine line and claim that since they're obviously traveling together they should have declared it as one...and then the onus is on you to prove otherwise.
I know a guy whom back in the days took 150k USD with him, his wife and a "niece". He was in the "pharmaceutical" business back in those days. I couldn't believe his stupidity...mind you that back in those days there were tons or Remesas and were pretty much unregulated. Luckily for him things weren't as stringent as now so he got it through.