Multiple AWS accounts with MacOS Safari and Passwords.app

I need to save and use several passwords for different accounts on AWS. The username is unhelpfully the same for each account. Unfortunately the MacOS Password App keeps adding a generic (regional) signin URL to the Passwords.app on my behalf. Here’s what happens:

Passwords.app seems to view the redirect page as primary and acts accordingly with the first supplied set of credentials.

So my question is, how do I get Safari/Passwords.app to recognise the different URLs and/or ignore the subsequent redirect?