How to setup additional Currency for Debrief Expense Items

We are not sending the Expense info to the Costing or Sales Order.

We just need to capture what was the Expense Incurred by the Field Service Engineer. However, with one Debrief Item "FS Expense" we are expecting the Field Service Engineers from different Regions to use the same Debrief Item for Expense, but put in the Currency according to their Region.

We are not intending to have a Price list for Debrief items as we are not creating a Sales Order or showing the Price in Manage Charges Screen.

Where is the setup to manage the Currency Dropdown in Add Expense Page?