How to create custom cards that leverage the member/subscription status

I’d like to create cards that I can use to display content to users depending on their subscription/membership status.

A little more detail is found here: Hide parts of the content for non-subscribers

The gist is that the card holds two types of content:

  1. A preview content if you’re not a (paid) member
  2. The actual content if you’re a member.
What non-subscribers see What subscribers see
Discover the 7 elements for [something relevant for audience]
Sign up to get access for this part of the content.

[Sign-up button]
If you want to truly succeed at [something relevant for audience], then consider using these 7 techniques:

1. Foo
2. Bar
3. …

I spend the last days looking for info into how to hook into the rendering of the content by browsing the code, but I can’t manage to find anything that points me to the right direction.

Is there any dev here, that can help me find an angle to do this?

In a way this would be similar to this: Intelligent Call to Action Buttons for Ghost via Outpost