As of the moment, there isn't an integrated way to match an expense to multiple downloaded bank transactions. It is recommended to enter your expenses based on the date and amount of the downloaded transactions so you can easily categorise them.
In the same manner, here's an article you can read to learn more about how you can match your transactions: Categorise and match online bank transactions in QuickBooks Online.
On top of that, I've also included this reference helpful with the steps needed in matching your bank account with transactions on your bank statement: Reconcile an account in QuickBooks Online.
If there's anything else that I can help you with, please let me know by leaving any comments below. I'll be here to lend a hand. Take care and stay safe!