The Trust Services contains the following statement: 

Content IGs will identify specific data elements within resources that need to be processed by Trust Services based on the use case.

The trust service operation definitions only accept a bundle as a parameter.  If content IGs will supply additional information to the trust services than the means in which this happens need to be defined and included (At a minimum in the narrative content) within the operation definitions. 

The means in which Content IG's will specify this data also needs to be defined.