my %one = ( "one" => 1, 
            "two"=> 2, 
            "three"=> 3,
            "four" =>4,
            "fice" => 5, );

my %two = ( "one" => A,
            "two"=> B,
            "iii"=> C,
            "iv"=> 4444,
            "v"=> 5555,  );

my @common = grep exists $one{$_}, keys %two;
@one{@common} = @two{@common};