There is a facility to restrict text in articles to ONLY those users who are subscribed to particular plans.

The documentation is here: http://membershipprodoc.joomservices.com/resources-access-restriction

To configure this in articles, see the note below (this is in the documentation link provided above):  

If the user is already subscribed to the plan, the text (in bullet point 2 above) will appear, otherwise the message below will appear, with a link to the subscription plans (the actual link you wnat to redirect TO is configured in the plugin "OS Membership URLs Restriction" with no 'HTTP' and no 'WWW'):

{mprestriction ids="1"}The text you want to hide must be inserted between here{/mprestriction}