Seconded.

If you'd prefer not to roll your own, I've got a similar function in my Data::DRef module on CPAN:

  use Data::Dref qw( set_value_for_keys );

  my %hash;
  
  set_value_for_keys( \%hash, 1, qw(a b c d) );
  set_value_for_keys( \%hash, 1, qw(a c d e) );
[download]

There's also a corresponding get_value_for_keys function, if needed...