The group interview was clearly just to weed out drug addicts and felons. Reasonable, given it was to be a financial call center. As long as you didn't leave when they mentioned the drug test, you got a callback within 24 hours. Drug test was offsite at a later date and could be postponed a week or two. Second phase was an in person one on one interview with a manager from the floor. Wear a tie to that one and make sure that person remembers your name in a good way and you've got a great gig.