Performing a custom currency translation for a subset of accounts is a scenario where an On-Demand rule would be an appropriate solution. An On-Demand rule is a type of business rule that can be executed manually by users on forms or Smart View worksheets. An On-Demand rule can perform calculations or transformations on selected data cells without affecting other data cells. For example, an On-Demand rule can be used to translate data from local currency to reporting currency using a different exchange rate than the default one for a subset of accounts.Oracle Financial Consolidation and Close 2023 Implementation Essentials Study Guide, page 61-62; [Oracle Financial Consolidation and Close Cloud Service Administrator's Guide], page 9-1.

You can copy these types of data:
Regular Data (including journals)
Override Data - rates and amounts entered on the Override Rates form for historical rate override accounts