If you cut out all the current diagnostic dumps and the CGI dependent stuff you get something like the following:

use warnings;
use strict;

my %cgiParam =
  (
  hiddenCity=>'1', borg=>'2', foocity=>'3', hiddendistance=>'4', bork=
+>'5', fooDistance=>'6',
  citydistance=>'7'
  );

my @cgiParamKeys = keys %cgiParam; # Store the %cgiParam keys into an 
+array

my @cityKeys;
my @distanceKeys;

foreach( @cgiParamKeys ) {
  if( /city/ ) {  #If a hidden city field found store it in an array;
    print "city: $_\n";
    push @cityKeys, $_; #Store the field in an array
    @cityKeys = sort @cityKeys;   #Sort the array
  }
  if( /distance/ ) { #If a hidden distance field found, store it in an
+ array
    print "distance: $_\n";
    push @distanceKeys, $_; #Store it in the array
    @distanceKeys = sort @distanceKeys;  #Sort the array
  }
}

my @hiddenKeys = qq(@cityKeys @distanceKeys);

foreach( @hiddenKeys ) {
  if(/city/) {
    print "$_";
  }
  if(/distance/) {
    print "$_";
  }
}
[download]

Which prints:

city: citydistance
distance: citydistance
distance: hiddendistance
city: foocity
citydistance foocity citydistance hiddendistancecitydistance foocity c
+itydistance hiddendistance
[download]

Does that demonstrate the problem that you have? If it does, can you describe the problem in the context of this example. If it doesn't, can you provide a similar example that shows the problem?