How Do I Consolidate My 4 Yahoo Email Address So I Can Receive Emails Through One Default Yahoo Email Account?

I would like to receive emails from all 4 Yahoo email accounts I have when logged onto my primary Yahoo email account. I have gone through Yahoo Mail => Check Other Mail => Edit => Mail Accounts but when I go this path I need to know a POP server to put in. I put in ... mail.yahoo.com ... but that does not seem to work. Is there any other way? Am I using the wrong POP server for Yahoo Mail? If so, what is the right POP server that I should be putting in to receive emails from my other Yahoo email accounts through my primary email account?