Membership subscription for RSS feed

[Nguyen]

I am a Vivvo certified developer, who is looking for a sub-contractor to do a small project as below:

My client has a Vivvo RSS feed - full article feeding to a number of other Vivvo sites. These sites pay a membership subscription to the main site (RSS feed provider.) The main site owner want to cancel subscription of non-paying RSS receiving sites based on a Vivvo plugin or customization to Vivvo.

For easier demonstration:
Site A is providing full article RSS feed to site B, C, D, E, F (same content for all sites.) All sites B, C, D, E, F are paying to Site A for receiving RSS feed.

Now sites C and F are no longer paying, Site A need to stop sites C and F receiving Full article feed without affecting other paying sites.

[Dugi]

Probably not the answer you are looking for but a quick fix
can you not put something in you htaccess file to say when this ip or url tries to access this url send them to the payment page?

[Nguyen]

Can you do full membership administration like renew, postpone, cancel membership?