It is possible to implement temporary (site) access to users (through User management) and organizations (through Site sharing).
There are 4 applications: For new users, existing users, when starting site-sharing and to end site sharing.
Temporary access for new users:
When inviting a new user to your organization, move the Temporary access slider to the right and enter an end date. This will enable temporary access to that user until the chosen date.
Temporary access for existing users:
In User management, open the menu by clicking on the three dots beside the user's name. Select "Set temporary access". Slide the Temporary access slider to the right and select an end date. That user's access will end on the chosen date.
Temporary access when sharing a site with an organization:
When enabling site sharing with an organization, slide the temporary access slider to the right. Select the date you want to stop sharing your site with the organization.
Temporary access when already sharing a site with an organization:
Under the 'Sites" tab, open the menu by clicking on the three dots beside the organization you want to stop sharing with. Select "Set temporary access" or "Edit shared permissions". Slide the Temporary access slider to the right and select an end date to end access to all users of the organization as of the chosen end date.