Multi-Pass Rendering
Meshes and render instances support Cinema 4D's "Compositing" tag, object buffers, and multi-pass rendering:
Object Buffers (Particles and Render Instances)
The workflow is almost the same as in Cinema 4D
Attach your objects to the fluid container.
Apply a "Compositing" tag to each object.
Under Compositing tag > Object Buffer define the object buffers.
Open Cinema 4D's "Render Settings" (Ctrl/Cmd + B).
Click on "Multi-Pass..." and create an appropriate number of "Object Buffer" nodes.
Adjust the "Group ID" parameters according to the "Buffer" values of the tag.
Group ID 1 corresponds with "Buffer" 1 from the "Compositing" tag.
Object Buffers (Meshes)
The workflow is the same as described above, but with one difference:
The "Compositing" tag has to be applied to the mesh directly.