RealFlow | Cinema 4D's multi-physics solver is capable of calculating interactions between different fluids, materials, and deformer:

• A RealFlow node's "Links" field is of particular importance, because it defines which scene elements will be able to interact, react on daemons, or collide with objects. 
• In terms of linking, rigid and elastic deformer are treated in exactly the same way as fluids – and it is even possible to combine deformer and fluids.
• There is a simple rule: Interacting scene elements have to be connected through their "Links" fields.

Example 1

In this example, two fluid containers, A and B, are able to interact with each other and both fluids are affected by a "Gravity" daemon:

Example 2

Let's keep the setup from above, but this time we add a "k Age" daemon that will only delete particles from "Fluid_B":

Example 3

Of course, every fluid container needs its own emitter to create particles. "Fluid"_A" is attached to "Emitter_A", B to B:

Example 4

Now we also add a collision object to catch the particles. Collision objects are defined through a "Collider" tag and this tag has to be aware of the two fluid containers as well: