#!/usr/bin/perl -w
use strict;

my $entries;

while ( my $line = <DATA> ){
		$line =~ /\d?\W*(gr\d)\W*(\d*-\d\d-\d\d)/;
		next if ( !$2 );

		my $group = $1;
		my $date = $2;
		$date =~ s/-//g;

		if ( ! defined( $entries->{$group})   || 
				( $entries->{$group}->{date} < $date )  ){
				$entries->{$group}->{date} = $date;
				$entries->{$group}->{entry} = $line;
		}

}

foreach (keys( %{$entries} )){
		print "entry: $entries->{$_}->{entry}";
}




__DATA__
item  group  entry_date
34     gr1    2003-03-02
12     gr1    1990-03-14
39     gr3    2002-04-11
66     gr4    2006-03-16
32     gr3    1998-02-13
90     gr1    2004-06-15
55     gr4    1999-06-15
etc ...