my %checks = (
               '123:C' => [ 'A[0-7]' ],
               '456:D' => [ 'B[8-9]', 'B1[0-5]' ]
             );

while ( <DATA>)
{
 chomp;
 my $check = $_;

 my $matches = 0;
 #-- get the trailing key
 my $first_part = "";
 my $key = "";
 if ( $check =~ /(\w+):(\w+:\w+)$/ )
 {
  $first_part = $1;
  $key = $2;
 }

 #-- look up key in our checks hash
 foreach my $match_pattern ( @{$checks{$key}} )
 {
  if ( $first_part =~ /$match_pattern/ )
  {
   print "Line $_ matches $match_pattern:$key\n";
   $matches = 1;
  }
 }
 print "Line $_ doesn't match\n" unless ( $matches );
}

__DATA__
A4:123:C
B8:456:D
B11:456:D
X11:456:D

##</code><code>##

Line A4:123:C matches A[0-7]:123:C
Line B8:456:D matches B[8-9]:456:D
Line B11:456:D matches B1[0-5]:456:D
Line X11:456:D doesn't match