Hi Brent

Thanks for your patience - hopefully the below clarifies how things are shared with multitenancy 

The tenant admin can only share their resources with their tenant users or users who are not a member of a tenant. 

If a user is a tenant member, all their Engage activity (e.g. workspaces and resources) is restricted to their tenant, and invisible to users outside the tenant. Having said that, a tenant member can share their content with users outside the tenant, but only those who are not members in another tenant.

If a user isn't a member of any tenant, any resources they create will be stored at site-level, and will be accessible to all site users (as well as all tenants,

Also, 'Find learning' respects tenant membership. For example, a tenant member will be able to see all the public resources in their tenant AND at site-level, while a site-level user will only see site-level resources, but not those which belong to tenants.

For courses this is different. When you create (or edit) a course you can control what category it will be in, so depending on your permissions you can select sitewide or tenant-specific categories. However, resources are forced into hard-coded categories based on the author's tenant membership. 

regards