Order of Deduction Question

Where do I see the setup order in which deductions are taken from employees?  Current setup, any elements that are eligible for 403b are taken first, then medical, dental, social, etc. This has caused issues with some per diem employees and put them into arrears as not enough hours have been worked. What should be happening is Medical should be paid first, the social, etc, then the different should be going into their 403b. Where can I see this setup, and what are my options for updating without creating all new elements to include iterative processing? -

Thanks,

Kevin