Postfix: how to set up TLS/SSL for all but a few servers?

Question

postfix

Situation: the organization has a postfix mail server, raised by no one knows who knows when. It is necessary to configure the reception of mail so that everyone goes to it only via tls / ssl, with the exception of several separately registered mail servers, which should go via regular smtp. The option to reconfigure those servers to ssl is out of the question for reasons beyond our control.
Please let me know if this is possible and where to look.

Answer 1

In /etc/postfix/master.cf duplicate the smtps entry, specify for the second network with which authorization will be only via SSL (or repeat the entry for each IP).
It should look like this:
smtps inet n - - - - smtpd
...
-o smtpd_tls_security_level = may
-o smtpd_tls_auth_only = yes
...
123.123.123.123:smtps inet n - - - - smtpd
...
-o smtpd_tls_security_level = may
- o smtpd_tls_auth_only = may
...