BTW do NOT put these in the bank unless you are fastidious about getting them before you head to SMV,  Blizzard will NEVER let you have more than 12.  I had 11 and killed prolly 40-50 of these and then I realized I had one in the bank from when I grouped it.  You CAN group this - you need a TOTAL of twelve between all in the group ( you can all get 12 each and get it over for a while if you are a tight knit group or to save yourselves a bit of punishment later so you don't have to get all twelve) My suggestion is, if in a group, everyone get all 12 - that way when and if you solo - you don't need to get all 12