You can only reimburse employees with a US bank account from Spendesk. International transfers must be made from your bank account.
To do this, use the CSV option in Expense Claims > Schedule Reimbursements.
Then, use that CSV to make a manual transfer to your employee.
if an employee has a US account, use "Spendesk directly".
if an employee has an international account, use "CSV" and make a manual transfer from the bank.