sorting a multidimensional array

I try to sort an array called $info which is tridimensional , the first value is the number of elements , the second value is used for the sort ( name of the variable ) and the third is a positionnal value for elements multivaluated . What can i do to sort under an element in second position without losing the link beetwen the others elements example Before the sort i have $info[0]["el"][0] = 120 and info[0]["el1"][0] = cou1 $info[1]["el"][0] = 100 and info[1]["el1"][0] = cou2 $info[2]["el"][0] = 110 and info[2]["el1"][0] = cou3 $info[3]["el"][0] = 140 and info[3]["el1"][0] = cou4 My purpose is to sort with ["el"] and the values of ["el1"] remains linked $info[0]["el"][0] = 100 and info[0]["el1"][0] = cou2 $info[1]["el"][0] = 110 and info[1]["el1"][0] = cou3 $info[2]["el"][0] = 120 and info[2]["el1"][0] = cou1 $info[3]["el"][0] = 140 and info[3]["el1"][0] = cou4 What can i do ? any clue is wellcome . Guilhem michel