How to switch two email accounts interchangeably??

Before hotmail had changed their layout, I had two email accounts in which were linked together and I could interchangeably switch them to check emails by a click in the list of options on the top right-hand screen. I have two accounts because one is for formal use (business) and my other was for personal use (coupons, shopping promotions, etc.), both are two different email addresses, but it was an easy function for me to switch. Now that the button isn't there anymore, does anyone know how I could insert that setting? I apologize if it is right in front of me, but I really don't know where that is. It was a great feature, and I hate how I now have to individually sign out of each account, sign on and put my password again.