[BigDan]

var arr:Array = new Array();
arr[0] = {id:1,numbers:[1,2,3]};
arr[1] = {id:2,numbers:[2,3,4]};
arr[2] = {id:3,numbers:[3,4,5]};
arr[3] = {id:4,numbers:[4,5,6]};
for(var i=0;i<=arr.length-1;i++){
 for(var j=0;j<=arr[i].numbers.length-1;j++){
  if(arr[i].numbers[j] == 2){
   trace(arr[i].id);
  }
 }
}

Этот вариант удобней.