my @arr = ( 'NA', 'EU' );
my $base = 'Countries';

process_full_list( $base, @arr );

sub process_full_list {
	
	my ($base1, @arr1 ) = @_;
   
	my $elem;  

	print "############################\n";
	print "In process full list: $base1 : @arr1\n";
	print "############################\n";
 	
	foreach $elem ( @arr1 ) {
   	process_next( $base1, $elem);
 	}
}

sub process_next {
  
   my ( $r_base, $r_elem ) = @_;
   my ( $new_base, $new_elem, @new_arr);

   print "\tIn process next: $r_base : $r_elem\n";
	
	# The if loop is temporary. It will be replaced by a 
	# sub that will fetch the next array to process by 
	# reading from the file based on the search string.
   if ( $r_elem eq 'NA' ) {
   	@new_arr = ( 'US', 'CA' );
   }
   elsif ( $r_elem eq 'EU') {
   	@new_arr = ( 'FR', 'IT' );
   }
   elsif ( $r_elem eq 'US') {
   	@new_arr = ( 'NY', 'LA' );
   }
   elsif ( $r_elem eq 'CA') {
   	@new_arr = ( 'TO', 'VC' );
   }
  
	if( defined ( $r_elem ) && (@new_arr) ) {
      print "\tnew_base = $r_elem: new_arr=@new_arr\n";
      process_full_list( $r_elem, @new_arr );
   }
	  
}