Jobsite help

Hey, just a personal issue I'm having, maybe someone else is too. I have 2 sims at the Movie Studio, one is a director and one isn't a specialist yet. For the costume dept., the task is 30 minutes long. All the other tasks are 2,5, and 10 minutes (roughly). This is creating a pileup of customers that all are needing to do the 30 minute task, and one of my Sims is left with nothing to do, no one to help. Any tips on dealing with this?