foreach my $num (1..5) {
 foreach my $letters ( ('TS','SA') ) {
  my $name = "cluster".$num."_".$letters;
  foreach ( @{$cluster{$name}}) {
   do_action($_);
  }
 }
}

##</code><code>##

my @clusters = 
(       
        ['h1', 'h2', ... ],
 ['h8', 'h9', ... ],
 ['h16', 'h17', ... ],
 ['h24', 'h25', ... ],
 ['h32', 'h33', ... ],
);

##</code><code>##

my @clusters = 
(       
        'h1', 'h2', ... ,
 'h8', 'h9', ... ,
 'h16', 'h17', ... ,
 'h24', 'h25', ... ,
 'h32', 'h33', ... ,
);