Sounds like a UI nightmare. This game already has problems managing moving inventory items around. Do you ever have a retainer up when your duty pop? 'Unable to transfer item because of duty window' something message. As if the game is going to completely delete or duplicate an item if you enter a loading screen. I'm not sure the base system would even be able to handle moving an item directly from one retainer to another. Not without extensive coding efforts which will probably still bug out and delete items requiring emergency maintenance, that is.