Best way to set up multiple emails/domains in Office 365?

I have a client that has 4 separate domains, with an email account on each. The client will be migrating to Office 365, and would prefer to receive ALL of her current email from the 4 separate emails into a single account in Office 365. The important part is that she wants four separate folders for her email, so that each current account would be a subfolder in her Exchange and have its own inbox and sent items as follows:

User Mailbox:

    email@domain1.com

        Inbox

        Sent

    email@domain2.com

        Inbox

        Sent

    email@domain3.com   

        Inbox

        Sent

Additionally, she wants to automatically reply from the account the email was received in., so that if she hits REPLY in email@domain1.com, the reply will come from that account.