How to set up Geoserver app-schema feature chaining?

Question

I am using Geoserver 2.12 with the application schema plugin to map a PostGIS database schema to the GeodesyML schema. I need to set up a WFS request that returns GeodesyML output such as:

<wfs:member>
  <geo:GeodesyML gml:id="geoml_monuments.fid-39d8a647_15cd161ff6e_-7e89">
     <geo:Site>
        <geo:installedDate>2001-09-12T06:00:00Z</geo:installedDate>
     </geo:Site>
     <geo:Monument>
        <geo:height />
        <geo:foundation />
     </geo:Monument>
     <geo:siteLog>
        <geo:siteIdentification>
           <geo:siteName>Cordell, OK</geo:siteName>
           <geo:fourCharacterID>SG19</geo:fourCharacterID>
        </geo:siteIdentification>
        <geo:siteLocation>
           <geo:city>Norman</geo:city>
           <geo:state>Oklahoma</geo:state>
           <geo:countryCodeISO>United States</geo:countryCodeISO>
           <geo:tectonicPlate>North America</geo:tectonicPlate>
           <geo:approximatePositionITRF>
              <geo:cartesianPosition>
                 <gml:Point gml:id="cart.geoml_monuments.fid-39d8a647_15cd161ff6e_-7e89" />
              </geo:cartesianPosition>
              <geo:geodeticPosition>
                 <gml:Point gml:id="latlon.geoml_monuments.fid-39d8a647_15cd161ff6e_-7e89" srsDimension="2">
                    <gml:pos>-98.977854677 35.355545782</gml:pos>
                 </gml:Point>
              </geo:geodeticPosition>
           </geo:approximatePositionITRF>
        </geo:siteLocation>
     </geo:siteLog>
  </geo:GeodesyML>

I have succeeded in doing this when the data is all stored in a single materialized view in my database. Unfortunately this is too limiting and I need to be able to pull things from multiple views. Specifically I want to be able to pull the geodeticPosition and cartesianPosition geometry objects from a PostGIS view called location_view and all the rest of the data from site_view. I believe the way to do this is by Feature Chaining wherein I need to set up a top level mapping file which pulls data from site_view and <Include>s a second mapping file that pulls from location_view. In each of these mapping files, what do I need to have in the <targetElement>, <targetAttribute>, <linkElement>, <linkField>, and <sourceExpression> fields? Alternatively, is there an easier way to pull data from two different tables/views into a single mapping file?

Here is an example provided from the Geoserver docs on Feature Chaining