If you are using RHUI the endpoint should have a repo config locally. If this is the case you will want to take a look at TaskID: 13 - Enable custom repository support - Red Hat Enterprise Linux. This will tell the endpoints to download patch content from the locally configured repos.
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When using the RHSM Plug-in all content is downloaded to the BigFix server first and cached there before being distributed out to relays, and then endpoints. When using the endpoints local yum repo configuration, there is no caching of content and each individual endpoint downloads the patch content. So the con would be:
no cached content
Endpoints downloading content individually from the vendor