Hey,
I've tried making a mass auction before, for me the logic was simple.
Leaders makes a long bid start string, !massbid start <item1><item2><item3><item4>... Then the users are presented with a blob where you see the full list of items that are up for auction, what they then do is vote what item that should be next as up for auction (using the regular !bid start feature). But how it looks, is that the users think this was to complicated.
So back to the drawing board.
Ideally id like to start all items at once, then made into individual auctions, all running at same time, presented with a blob. Im sure some you have seen one like this before. Tho there are some technical issues with this. Bot is flooded with messages and there is a tell lag, without proper handling a user could end up getting the tell "you were outbid on item xxx" 5 minutes after the auction has ended. Having the bot queue the message, and add the approx time cause of lag is not a too big issue but i don't want to have a auction last for 20 minutes either.
Also to battle "ninja bid" remember all items would run as individual auctions but run at same time. But ending when its ended like the normal bid feature. First after all items have been won by someone everyone are presented with a blob that shows the winners.