I assume fragmented batches (and they will all be fragmented), will be merged. So refunded chips in the GB will be started to refund first batch 5, then 4 etc.
Batch 6 is a different thing all together since it was split between groupbuys.

How the chips advance in the queue is unclear to me as of yet. Lets say a batch 5 continued order will be moved to fill chipspace in batch 4, would that mean a genuine batch 4 buy needs to be moved to batch 3? I think some fairness and luck comes into play, especially because of very different order sizes... it might quite literaly be puzzling .