How to automatically look back unrealized gains/losses to realized gains/losses

You are a Japanese company.
Suppose that in Journal Entry Transaction, the company borrowed from an overseas bank on 2024/08/01 in a foreign currency transaction.

(Debit) Savings account $100,000
(Credit) Long-term debt $100,000

The exchange rate at this time is 1USD=160JPY.

Assume that a currency revaluation is performed on 2024/08/31.
The exchange rate at that time is 1USD=170JPY.

When the currency revaluation is executed, the following journal entry is recorded.
(Debit)Unrealized gain/loss 1,000,000JPY
(Credit) Long-term debt 1,000,000 JPY

Normally, when the long-term debt is repaid later, the unrealized gain/loss should be automatically transferred to the realized gain/loss.