use Tie::IxHash;
use strict;
my $HoHoH = {};
tie %{$HoHoH->{$_}}, 'Tie::IxHash'
  foreach qw(alice john andy);
                                                                                
# rest of code as above
# output:

alice
        aaaa    time = 20:00:00
        www     time = 22:00:00
        bbb     time = 25:00:00
 
andy
        xxx     time = 24:00:00
        yyy     time = 26:00:00
 
john
        ccc     time = 21:00:00
        aaa     time = 23:00:00