c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $pair = qr{ (\d+) \s+ ([[:alpha:]]+) }xms;
 ;;
 my $record = '1 A 1 B 2 G 2 H 2 V';
 ;;
 my %hash;
 while ($record =~ m{ \G \s* $pair }xmsg) {
   push @{ $hash{$1} }, $2;
   }
 dd \%hash;
 ;;
 $hash{$_} = join ':', @{$hash{$_}} for keys %hash;
 dd \%hash;
"
{ 1 => ["A", "B"], 2 => ["G", "H", "V"] }

{ 1 => "A:B", 2 => "G:H:V" }
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