!/usr/bin/perl

use strict;
use warnings;

my $title;
while ( <DATA> )
{ 
  chomp;

  if ( /\(\w+\-\d+\)$/ )
    { $title = $_; }
  else
  { 
    s/(?:^|\s)(\d\-\d\w{2}(?:\.\w+)?|[A-Z]\d{2}(?:\.\d+)?)/\n$1/g;
    foreach my $line ( split ( "\n" ) )
    { 
      next if $line !~ /^(\d\-\d\w{2}(?:\.\w+)?|[A-Z]\d{2}(?:\.\d+)?)/;
      print "$title;$line\n";
    }
  }
}

__DATA__
Titel Text (A12-3)
3-123.7 Just another text 3-123.8 Some more text
A12.34 Another item B56.78 Yet another item
Another Titel Text (B23-9)
1-22a.b Just another text
2-3cd.e Some more text
W12.34 Another item
Z56.78 Yet another item
Some trash
Some trash

##</code><code>##

Titel Text (A12-3);3-123.7 Just another text
Titel Text (A12-3);3-123.8 Some more text
Titel Text (A12-3);A12.34 Another item
Titel Text (A12-3);B56.78 Yet another item
Another Titel Text (B23-9);1-22a.b Just another text
Another Titel Text (B23-9);2-3cd.e Some more text
Another Titel Text (B23-9);W12.34 Another item
Another Titel Text (B23-9);Z56.78 Yet another item