my (%data);
while (<DATA>) {
  chomp;
  # $_ contains '100-233,MA,150:250', for example
  my @initialparts = split( /,/, $_ );
  # @initialparts now contains ( '100-233', 'MA', '150:250' )
  my @leadparts = split( /-/, $initialparts[0]);
  # @leadparts now contains ( '100', '233' )
  push( @{$data{$leadparts[0]}{$initialparts[1]}{'items'}, 
      $leadparts[1] );
  # @{$data{'100'}{'MA'}{'items'} = ( '233' )
  if (scalar(@initialparts) > 2) {
    # Do only if there was a last term
    my @tailparts = split( /:/, $initialparts[2] );
    # @tailparts now contains ( '150', '250' )
    push( @{$data{$leadparts[0]}{$initialparts[1]}{'data'}, 
        @tailparts );
  }
}
open(OUTF, $0 . '.out') or die("Can't open $0.out for output: $!\n");
foreach my $f1 (sort(keys(%data))) {
  # Personally, I prefer data sorted, 
      # although you could leave out the sorts above, and following
  print $f1, "\n";
  foreach my $f2 (sort(keys(%{$data{$f1}}))) {
    print $f2, "\n";
    my $v4 = '|'
    if (defined($data{$f1}{$f2}{'data'} {
      $v4 .= join( ':', sort(@{$data{$f1}{$f2}{'data'}) );
    }
    foreach my $v3 (sort(@{$data{$f1}{$f2}{'items'})) {
      print $v3, $v4, "\n";
    }
  }
}
__DATA__
100-233,MA,150:250
100-344,MA,350:
200-400,ER,
200-300,ER,576
100-250,MA,150
75-300,MA,350

##</code><code>##

#
# Variables, throughout run
#
# Read line 1
$_ = '100-233',MA,150:250
@initialparts = ( '100-233', 'MA', '150:250' )
@leadparts = ( '100', '233' )
%data = { '100' => { 'MA' => { 'items' => ( '233' ) }}}
@tailparts = ( '150', '250' )
$data = { '100' => { 'MA' => { 'items' => ( '233' ), 
                               'data' => ( '150', '250' ) }}}
# Read line 2
$_ = '100-344,MA,350:'
@initialparts = ( '100-344', 'MA', '350:' )
@leadparts = ( '100', '344' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250' ) }}}
@tailparts = ( '350' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350' ) }}}
# Read line 3
$_ = '200-400,ER,'
@initialparts = ( '200-400', 'ER' )
@leadparts = ( '200', '400' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400' ) }}}
# Read line 4
$_ = '200-300,ER,576'
@initialparts = ( '200-300', 'ER', '576' )
@leadparts = ( '200', '300' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ) }}}
@tailparts = ( '576' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ), 
                               'data' => ( '576' ) }}}
# Read line 5
$_ = '100-250,MA,150'
@initialparts = ( '100-250', 'MA', '150' )
@leadparts = ( '100', '250' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344', '250' ), 
                               'data' => ( '150', '250', '350' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ),
                               'data' => ( '576' ) }}}
@tailparts = ( '150' )
%data = { '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350', '150' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ), 
                               'data' => ( '576' ) }}}
# Read line 6
$_ = '75-300,MA,350'
@initialparts = ( '75-300', 'MA', '350' )
@leadparts = ( '75', '300' )
%data = { '75' =>  { 'MA' => { 'items' => ( '300' ) } },
          '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350', '150' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ),
                               'data' => ( '576' ) }}}
@tailparts = ( '350' )
%data = { '75'  => { 'MA' => { 'items' => ( '300' ), 
                               'data' => ( '350' ) }},
          '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350', '150' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ), 
                               'data' => ( '576' ) }}}
# In loop
%data = { '75'  => { 'MA' => { 'items' => ( '300' ), 
                               'data' => ( '350' ) }},
          '100' => { 'MA' => { 'items' => ( '233', '344' ), 
                               'data' => ( '150', '250', '350', '150' ) }}, 
          '200' => { 'ER' => { 'items' => ( '400', '300' ), 
                               'data' => ( '576' ) }}}
$f1 = '75'
$f2 = 'MA'
$v4 = '|350'
$v3 = '300'
$f1 = '100'
$f2 = 'MA'
$v4 = '|150:150:250:350'
$v3 = '233'
$v3 = '344'
$f1 = '200'
$f2 = 'ER'
$v4 = '|576'
$v3 = '300'
$v3 = '400'
#
# Output, from run
#
75
MA
300|350
100
MA
233|150:150:250:350
344|150:250:350
200
ER
300|576
400|576

##</code><code>##

    if (defined($data{$f1}{$f2}{'data'} {
      my (%uniq);
      foreach (@{$data{$f1}{$f2}{'data'}) {
        $uniq{$_}++;
      }
      $v4 .= join( ':', sort(keys(%uniq)) );
    }