A Related Organizational Membership  and Organizational Membership are allowed at the individual level. 

The Related Organizational Institutional Membership allows an organization to have a collection of members called a “bundle” that are linked together and managed by one member, the bundle administrator. All of the members in each bundle share the same renewal date, status, and membership level. A Related Organization can have unlimited members provided they are employees of the organization. All memberships are good for one-year, starting in July and ending in June.

Please note that the bundle administrator is the only one that can add members to a bundle. Once you have paid the fee, go into your profile and add your institution members. Each member must have an email address in order to login.