Email Server Issue

Hi- Back Story - My ISP blocked port 25 outgoing ( so whenever it connects to smtp.google.com etc mail server its timed out ). I tried changing the port in WHM -> Exim but still it doesn't work. As alternative I used mailgun but I stopped using it due to some reason. (That's the past story now the what I want to do is following ) I have 2 servers ( Server A, Server B ) On both of them WHM is installed On Server A ( Port 25 outgoing is blocked and can't send email ). But on this server all the domains exist and data On Server B ( The email works fine and smooth ) Now what I want is to setup Server A to send email through Server B ( and use Server B as my SMTP ). I searched alot and can't find any article for that a solution would be great Thank you.