Multiple feeds for one provider

From Xcri

While typically each provider creates a single catalog feed for all its courses, in some cases it may be more practical for individual faculties, departments or colleges to offer a feed of its courses. An aggregator must then support collating these courses in relation to a single provider.

For this to work, the provider must:

1. ensure each feed uses the same identifier for the provider

and the aggregator must:

1. not delete any courses omitted from a feed until all feeds for the provider have been collated

This pattern is used by Oxford University.