These group interviews are SW's way of weeding out the unqualified very quickly.
Expect a mechanical aptitude test as well as an ATP 50 question test. They will take your resume and test results and if you meet the mins and did not stand out by having a "172 sky-god" attitude, you can expect an invite to an interview in SLC within a week..maybe two. No class dates have been ever given out (as far as I know) without a trip to SLC for a sim check and formal interview.

Good luck-
ps study your jepps