Most efficient Martial Arts to defend against multiple opponents?
I've trained in boxing and brasilian jiu jitsu, but even with both of those I can only work one opponent at a time. Now, being reasonable and not a Bruce Lee movie, what would be the most effective martial arts to fight two or more opponents at a time? Taking practicality into consideration, I don't want to completely destroy everyone, I just want to defend myself against multiple attackers. Let's assume these guys are mildly experienced; gone out mugging many a dozen times, know how to fight a little on their own, but nothing amazing a blue belt in TKD couldn't do.