That's a tough question. LW is designed for public sharing, however I believe there are plans for some time in future to have some privately shared files. What you can do to send files to your friend is, email them magnet links of your files. See How to use Magnet Links & Direct Connect. As this technique is easier than direct connecting. You could monitor your upload window in your monitor window, if you see someone trying to upload the private files, then cancel them off the list.