%hash{@key1} => [@array1, @array2, etc];
%hash{@key2} => [@array1, @array2, etc.];

##</code><code>##

%hash{@key1} => [@array1, @array2, "abc"];
%hash{@key2} => [@array1, @array2, "abc"];

##</code><code>##

push (@{$hash{$key}}, (@array1, "abc"));