Adding multiple cash flow journal entries to a journal voucher

When I use Di to add journal voucher documents, adding multiple cash flow journal entries to the journal voucher will result in an error for invalid cash flow primary items. You can successfully add the journal when the first journal has cash flow and the other journals have no cash flow. After trying, it was found that there could be at most one such cash flow journal. I also tried working through the service tier, but couldn't find a way to add multiple journal entries to the journal voucher. I only found a way to add a journal entry under the service tier. Can you tell me how to add multiple cash flow journals under journal vouchers? I'll be grateful for helping me