The RelatedToOrganisation field is one of the set of RelatedTo fields which can be used to search the "RelatedTo" (Destination) end of a relationship.
When querying relationships in a sub-select, RelatedToOrganisation can be used to filter the RelatedTo end of the relationship to only include items within the selected organisation. It works in the same manner as the Organisation field.
Note: Currently all Enterprise Tester licenses are limited to a maximum of one Organisation, and so this field and Organisation is of little practical purpose to end users.
All entities which are related to an entity within the organisation 'My Organisation':