You can invite one person or a group of people to view a portal when sharing it.
After you've created a portal, simply click the Share button. From the portals Dashboard, select the Options menu > Share.
Enter names or email addresses to invite people to a portal, then choose to allow them to view or edit the portal. Viewing allows them only to see the assets. Editing allows them to add sections, change the banner image, update descriptive text, enable searching, allow downloading, change how many assets display on a page, and delete sections.
Enter a personalized message if you'd like, then click Invite. They'll receive an email to view the portal.