You can use pass contribution maps with your re-combination. In this example, there is a pass contribution map associated with the masterLayer. This pass contribution map contains the reflective objects in the model: the helmet and the metallic tubes.

To create a Reflection pass for the pass contribution map and add it to the re-combination

1. Create a Reflection pass from the Hypershade by selecting Maya > Rendering > Render Pass.
2. Select Window > Rendering Editors > Render Settings. Click the Passes tab.
3. Select your Reflection pass under the Associated Passes section and select your pass contribution map under the Associated Pass Contribution Map section. Click the to associate the Reflection pass with the pass contribution map.
   
   Close the Render Settings window.
4. In the Render View, select Render Target > None.
5. Click to render the Reflection pass.
6. Add the Reflection pass to the top of the Layered Texture node and use Add as the Blend Mode.
   
7. Ensure that your Layered Texture is connected to your Render Target.
8. In the Render View, select Render Target > renderTarget1.
   NoteThe button in the Render View toolbar should be locked for this render because all of your render pass results are already up to date and you are only working with the compositing graph.
9. Click .

The Render Target renders as follows.