Answer:
        Yes. However, at least one peer between the two in file sharing needs to be in a non-firewalled environment.
        Uploading the file on a network folder (also called nServer or PeerServer in LionShare documents) accomplishes this.

        Here is the procedure.
        If you and/or your partner are behind a firewall,
            1. put proper permissions on the file you would like to share,
            2. upload it to a network folder.

        Regarding how to upload files to a network folder,
        please refer to "Chapter 4 Share Using LionShare in Peer Users Guide 1.1".