outlook.live.com serves as an e-mail client on the cloud. Therefore, one should be able to add multiple e-mail accounts under a single outlook.live.com sign in.
This is not simple when one of your emails is a Hotmail account, because when you login to your hotmail.com account, the host switches to outlook.live.com.
Now how are your going to be logged in two outlook.live.com accounts at the same time in the same browser window/tab?
You are not.
But then how to you add the emails from your Hotmail account to your Outlook.live.com account open in the browser?
After experimenting with various IMAP and POP server configurations, this is what worked.