use 5.12.0;
use warnings;

my %HoA;

while  ( <DATA> ) {
  my @got = split;
  push @{ $HoA{ $got[0] } }, $got[2];
}

say "$_ - @{$HoA{$_}}" for sort keys %HoA;

__DATA__
aaa bbb 123
aaa ccc 234
aaa ddd 345
bbb ccc 456
bbb ddd 567
ccc ddd 678