You can control what document is retrieved in the "CCD REC: queryHIEForCCD" channel. The default is to get the first document returned in the adHoc response from the HIE's Registry (ITI-18). You can modify what ID is used in the following mapping node:

Here is an example xpath that can be used to get only documents that have "RelayHealth" as the author institution.
//ExtrinsicObject[Classification/Slot/@name='authorInstitution' and Classification/Slot/ValueList/Value='RelayHealth']/Slot/@name='repositoryUniqueId']/ValueList/Value/text()