How to use reject_rbl_client in postfix so that emails still go through but end up in spam?

Question

Email

Here is my postfix config:

smtpd_recipient_restrictions =
        # [.................]

          reject_rbl_client bl.spamcop.net
          reject_rbl_client zen.spamhaus.org

Now something is eliminated for good - REJECT - because of "bl.spamcop.net" and "zen.spamhaus.org" not even getting into spam at all.
How to make sure that those soaps that are now eliminated immediately because of bl.spamcop.net" and "zen.spamhaus.org" pass, but still end up in the spam folder?
I don't want to install anything additional.

Answer 1

Do not use rbl in smtpd_*_restrictions, but use scoring systems (amavis, rspam). In any case, postfix alone won't do it.