Maybe this post helps you: http://www.virtuallyghetto.com/2012/04/org-vdc-to-vcenter-resource-pool.html
It's about getting vCenter-information(MoRef of the resourcepool) from an org-vdc. But there is a similar way with providerVdcs. You just have to change the query type to QueryResultProviderVdcResourcePoolRelationRecordType. With the MoRef you can connect to your vSphere environment and retrieve the ResourcePool-Object.