use Data::Dumper;
use vars qw(%my_package::my_hash);

sub my_special_require ($) {
    my $pkg = shift;
    require $pkg;
    # alias %my_package::my_hash to %main::my_hash (aka %my_hash)
    *my_hash = \%my_package::my_hash;
}

my_special_require "dir_one/my_package.pm";
print Dumper(\%my_hash);

my_special_require "dir_two/my_package.pm";
print Dumper(\%my_hash);