A player had 4 RED Dragons already exposed on her rack from a previous call for one of the Red Dragons.  She declared Mah Jongg and picked up a 6 Bam and added 2 Jokers with it on her rack.  Then she proceeded to expose the rest of the Mah Jongg hand. She put three 8 Bams on the rack and then two 2 Craks and two 4 Craks.  Of course the hand was dead as she needed two 2 DOTS & two 4 DOTS because the hand calls for 3 suits. Now another player says that since she exposed the 6 Bams first with the 2 jokers, that that part of the hand was still available for exchanging the joker.  Was the Joker in the 6 Bam exposure still viable?  VS, CA