You may utilize a clearing account. Visit the following reference whether you are using QBO or QBD

https://quickbooks.intuit.com/learn-support/en-us/accounts-payable/set-up-a-clearing-account/00/2037...

If you frequently convert your fund in multi currencies, I would recommend opening a business account at TW. You may have a SGD account and an Euro account to convert your fund easily, then utilize the bank feeds to your QBO account.

https://transferwise.prf.hn/l/75dqNgB