When it restocks, does it restock only one item at a time? (Wondering if there is/isn't a ping group)

Yep, only one item at a time! As far as I know, there isn't a ping group. It wouldn't be usefull, since every item gets bought pretty much instantly. There is a board in Restocking though, where people post the item they bought and at which time.

http://subeta.net/forums.php/gotopost/822904

Okay, thank you for clearing that up! That explains why there isn't a ping group :) I'll just check back every so often and hope to grab something.