$VAR => {
    City-Center1=> {
        Data-items for first combination  }
    City-Center2=> {
        Data-items for second combination }
...
}
   

##</code><code>##

my %city_center_hash;

# Loading the data structure --
while <DATA> {
   ($variables) = split data line
   my $this_key = "$o_city|$o_tcenter"; # select an
                                        # appropriate
                                        # separater
   $city_center_hash{$this_key} = {
       data_item1 => variable1,
       data_item2 => variable2,
#      ...
       data_itemN => last_variable,
    };
}   
   
# ....
# ....

# Retrieve the data from the data-structure

foreach $cc_combo (sort keys %city_center_hash) {
 
    my ($this_city, $this_center) = split /\|/, $cc_combo;

    my $these_data = $city_center_hash{$cc_combo};

    my $variable_item1 = $these_data -> {data_item1};

    # Do something with the names and the first 
    # data variable
    # etc ....
}