[Exim] help required : custom black lists

Good day.

Is it possible to create a custom blacklist?

I keep getting spammed from jhgpdrdrmniog@??? but
the custom rule i have set up blocks the entire domain, not just the user.

Any help would be appreciated.

Rules below:

<snip>

acl_check_rcpt:
  accept  hosts = :
  deny    local_parts   = ^.*[@%!/|] : ^\\.

  accept  local_parts   = postmaster
          domains       = +local_domains

deny message = rejected because $sender_host_address is in a custom black
list at company name (company number)
deny hosts =
$lsearch{/usr/exim/custom_blacklist/custom_blacklist/$domain}}

# Deny unless the sender address can be verified.

  require verify        = sender

Regards,

Tom Kinghorn