One crafts a chest and places it down at his house. He can mark the chest using /chestdl to set that chest as a "download chest." He then goes to his enemy's headquarters, and steals the diamonds there. From here, he can quickly craft a chest that has a different crafting recipe and place it down, making it the "upload chest." OR He can just craft another chest using the vanilla recipe then use /chestul to set that chest as the "upload chest." Then you should know where I'm getting at now. Anything placed in the "upload chest" will directly go to the "download chest," at his house.
I think this does what yo uare looking for http://forums.bukkit.org/threads/me...t-with-minecraft-chests-1337-bukkitdev.46830/