Expense Report Audit Review

Hi Experts

I have a question in regards to the audit review process within ByD when submitting an Expense.

I have created a work distribution whereby all expense will be submitted to an auditor/review. Upon when the reviewer approves the report it should go to the Project Manager or Line Manager. My issue is that I have a couple of other users that have access to the travel and expenses WoC they are able to approve the expense as well. Is there a way to prevent users other than my reviewer/auditor from approving expenses. The reason I have other users access to the Travel and Expense WoC is that they will be responsible at time to enter expenses on behalf.

Thank you for your help

Antonio