Haddock support / tell ./setup where to find documentation of dependencies

I'm packaging all hackage packages for nix. I've already compiled 102 packages succesfully. Is there a simple way to do a ./setup haddock --dirs-containing-dep-docs=path1;path2;path3;path4 .. --install-to $out/haddock ? If not who is working on haddock stuff right now? Marc