I need an email client for multiple profiles/identities

A while back, there was Entourage which allowed different users to easily access their own email accounts without having to view anyone else's. When launching Entourage, a window would show the different accounts and you selected the one you wanted to use. It stored different email addresses as separate accounts so that several users could send and receive email through their own account without having to log into the Mac as a separate user.

This works well for our family as presently, I have only set up one log in user and there are four of us with four email addresses. So, instead of setting up logins for four different users just to use email individually, I want an email client that will separate each email profile/identity. Entourage appears only to be supported to Yosemite, so I need a new email client.

Is there such an email client out there that does this?

Thanks!