Unable to raise Expenses against a Project budget created in BU of different ledger

Fusion Expense does not allow raising an expense against a Project Budget defined in different ledger than respective User's ledger. Oracle simply mentioned this statement and confirmed that this functionality is not available.

However in real world, project resources do travel to project locations of different countries and those projects technically belonging to different BUs of different Ledgers. How to achieve this requirement ? Any direct solution or Effective workaround will be much appreciated.