How can I create additional context DFF with TransactionLineDff

Summary:

We need to map Order Management Fulfillment line data (specifically the Invoice Number) to Accounts Receivable DFF (Descriptive Flexfield) context-sensitive fields using Service Mappings. The seeded Service Mapping for Order Management is FulfillmentIntegration, and for the DFF, we use TransactionLineDff. However, TransactionLineDff only supports one context-sensitive DFF, which is already being used for another requirement.

Creating a copy of the TransactionLineDff entity is not possible, and we cannot create a new entity from scratch due to restrictions on custom entities and fields (which must be suffixed with _Custom). Additionally, we cannot create the standard fields required by the DFF, such as