How do I get the "Nepoleon Complex" achievement in Mafia Wars?

Tuesday, July 20th, 2010 at 12:55 pm

I am lv 232 with 501+ mafia members. Every time I try and fight another 501+ mafia I lose. Even if they are 10 lvls below me. And I figure that when I am a high enough lvl to beat them they will be high enough to defend. So is there some sort of secret that I can use to do this?