Wildcard blocking of spam MTAs?

[jassonmc]

I have an opnsense firewall (business edition) which utilizes plugins for postfix and rspamd. We sometimes receive spam mails, originating from different mail servers (sending SMTP), which are however from the same second level domain.

Example:
Spam sending SMTP server 1 has fqdn and also PTR entry: xyz.spamfreak.com
Spam sending SMTP server 2 has fqdn and also PTR entry: abc.asd.spamfreak.com

Is there a way to use a wildcard approach to block all and any communication with hosts having a PTR entry in DNS, that matches spamfreak.com at the end?
So it should block *.spamfreak.com but also *.*.spamfreak.com.