did a test on M33.90, submit a 4 jobs group running every 2 mins, all jobs in scheduled status. then hold the queue till the time for 1st job run, release it. see the 1st job runs immediately, all the other 3 jobs staying in scheduled status as original.
so my observation is only the job which is scheduled to run during queue hold time will start immediately after release, all the other jobs will follow its original schedule.