I just did a little test that had interesting results. If you sort the Saved Listing page by Title/Format (click on that header) and then select them for scheduling, they do appear on the scheduler page "in that order". I don't know if concurrent release will maintain that order, but it's worth a try.
It's the best suggestion I can make for use of bulk concurrent submission. However, ebay may process them (queue and list) differently, even with that or any method used on the Auctiva side of the submission.
Danno