I have an email id that has 4 email aliases. Currently any email sent to one of the aliases goes into a single inbox. I would like for there to be a way that each alias have a different mailbox so I know all the emails in that particular inbox was sent to one particular email. I know this has a very simple answer but I am having trouble finding it.  Also, I'm not sure if I am required to upgrade my account for those options. If anyone can assist me or point me in the right direction I would very much appreciate it. 

Thank you so much,

Andrew