An executable example:

use strict;

#create the exclusion hash outside of loop
#much cheaper than recreating though each pass inside of loop!
my %excluded_tables = ( 'SYSTEM' => 1,
                        'OBJECTS' => 1 );
                        
my @tables = qw(PEOPLE PLACES THINGS OBJECTS CONTACTS CUSTOMERS SYSTEM
+);

#foreach my $table_name (@tables) would be fine, too.
#assigning vars the value of $_ inside of a loop is kind of funky
for (@tables) {
  unless (exists $excluded_tables{$_}) {
    print "Assigning vars for $_\n";
    my ($table_1, $table_2, $table_3) =
      ("Table_name_A", "Table_name_B", "Table_name_C");
  } else {
    print "Skipping $_\n";
  }
}
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