suggestion:
it seems to be a orginzed auction type deal
Reason:
auction is just horble the way it is 2-4 auctions all going on at the same time the seller makeing it last longer then it should to try and get some one to bid
Other Information:
a mod or some might need to look at the server mod since i have no clue about any mod info or anything
Link to this plugin:
http://dev.bukkit.org/server-mods/iauction/