setting up rbl lists,host.allow, host.deny for customers as product?

Hello everybody, Due to some previous knowledge in the maintenance of RBL (In Regex format), host.allow and host.deny lists, we would like to offer our customers an own "Anti-Spam" package for free. This should be able to be booked normally by WHMCS free of charge and is automatically booked to the desired package. Are there any possibilities in CPanel to realize this? I've already seen that you can create RBL lists, but not how to offer these accounts as an extra package in conjunction with existing webhosting packages. I am happy about support and thanks in advance. Greetings