my %hash;
my $key;
while (<DATA>) {
  if (/^(\d-\d\d-.*)/) {  $key = $1 }
  else { push(@{$hash{$key}}, $_) if $key }
}

 while (my ($k,$v) = each %hash) {
   print "K=$k\n";
   print " V=$_" for @$v;
 }
__DATA__
$
1-11-ABC22 (12:12)   ABC 12 Foo Bar Foo Bar
Foo Bar Foo Bar

2-15-ABC33 (12:12)   ABC 12 Foo Bar Foo Bar
Foo Bar Foo Bar
--
1-11-ABC33 (12:12)   ABC 12 Foo Bar Foo Bar
Foo bar Foo Bar
--
1-11-ABC33 (12:12)   ABC 12 Foo Bar Foo Bar
Foo abr Foo bar
Foo Bar
Foo Bar
Foo Bar
--
2-15-ABC45 (12:12)   ABC 12 Foo Bar Foo Bar
Foo Bar Foo Bar

3-33-ABC15 (12:12)   ABC 12 Foo Bar Foo Bar