What means to receive and send mail from different mailers?

Question

Ruby on Rails

I need to implement the ability to receive and send letters from different mailers within the same system. Those. Let's say there is an office. It is assumed that Vasya will be able to indicate his mail in it and receive and send letters from this office. Similarly, Petya, and Masha and Seryozha. Such, the Bat is corporate, one might say.
Of course, I can use the mail gem and pull it with some kind of scheduler, but different mailers have different settings. Those. let's say Vasya specified imap and smtp of his Yandex mail and we can receive his letters. Then Petya comes, indicates his data, but his server, for example, does not support standard settings and requires, for example, enable_ssl => false (for example). How then to be?
Sorry, I'm confused, I understand that there is hardly a universal remedy, but somehow mailers like Bat and others work, so they somehow solve this issue.
I will immediately answer the question "why is this all?". It's trite, the authorities demand, so it's stupid to do it.