You're a Support Agent on the admin team for your Slack Enterprise Grid workspace.

Advise the employee to initiate one or more Slack Connect channels to collaborate with the external organization. The external organization can set up a free Slack instance if they are not already using Slack.

Advise the employee to request the external users be added to your identity provider (IdP) so they can authenticate to your workspace with SAML single sign-on (SSO).

Approve the employee's request, then invite the external users to your workspace as Multi-Channel Guests with a 12-month expiration date.

Advise the employee to set up a separate Slack workspace that is jointly owned by both organizations.