c:\@Work\Perl\monks>perl -wMstrict -le
"my @input = (
   'PING foo wrong',
   'PING check_nrpe wrong',
   'PING contact_groups wrong',
   'PING check_nrpe contact_groups wrong',
   'PING contact_groups check_nrpe wrong',
   'foo wrong',
   'check_nrpe wrong',
   'contact_groups wrong',
   'check_nrpe contact_groups BINGO!',
   'contact_groups check_nrpe BINGO!',
   );
 ;;
 my $check = 'check_nrpe';
 my $con   = 'contact_groups';
 ;;
 for my $list (@input) {
   next if $list =~ /PING/;
   ;;
   print qq{'$list'} if $list =~ /$check/ && $list =~ /$con/;
   }
"
'check_nrpe contact_groups BINGO!'
'contact_groups check_nrpe BINGO!'