If you don't want to add a contact to your contact lists/groups but want them to have access to a specific post, you can add a contact individually.

Enter the specific post, clip or press release, they should access and go to the access tab. 

Add contact for one-time access
Add the contact under 'Add contact' by entering the email address and clicking the 'Add' button to the right. The contact will appear under the email address field when added, and can also be removed from there by clicking the delete icon.

If the contact is not yet registered to the service, they will receive a registration email to create an account.