Where do the codes come from? If you have an array containing all possible codes, populating @UNSPECIFIED is easy. If there's no such list and the code can be anything, then @UNSPECIFIED is infinitely large.

#!/usr/bin/perl
use warnings;
use strict;

my @all = qw( 2770 27700 27701 27702 27703 27707 27709 277 0704 07049
              1a 1b 1c 1d 1e 1f 1g 1h );

my @diag_group_A = qw( 2770 27700 27701 27702 27703 27707 27709 );

my @diag_group_B = qw( 277 );

my ( %is_in_groupA,
     %is_in_groupB,
     %is_unspecified,
   );

@is_in_groupA{ @diag_group_A } = (1) x @diag_group_B;
@is_in_groupB{ @diag_group_B } = (1) x @diag_group_B;
$is_unspecified{$_} = 1 for grep ! $is_in_groupA{$_}
                              && ! $is_in_groupB{$_},
                            @all;
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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