If I have multiple 1099 div from same payer, how do I know which one I am reviewing?

Your bank or financial institution will have each account listed separately with 1099 for each one that pays dividends.  So you can compare those numbers to the ones downloaded through TT.  Or you can just start over and enter each account yourself.  I name mine based on last 4 of the account.  So XYZ Bank, #4524 and XYZ Bank, #4525...

You would need to compare the TurboTax entries with your actual Form 1099-DIV from the financial institution to know which one you are reviewing.  Account numbers are not required to be reported as part of the information sent to the IRS on your tax form, so TurboTax does not need that information.

@jackstraw75