I have a question. What settings do you need to change in order to have all of your emails get grouped up by sender?

I know that it can be done because I have multiple email accounts pinned and at least one of them does it which happens to be a yahoo email. I know that my main hotmail one does not however it did on my prior WP7.

I would like to be able to have my emails saved in threads by sender so I can easily view them from certain senders such as when I purchase apps from the store instead of having to go online.