...
The number of emitters, fluid containers (different fluids cannot interact), and daemons per scene is not restricted and you can add as many of these elements as you want – or as you computer is able to handle.
...
We recommend grouping all RealFlow | Cinema 4D elements under the “Scene” tree. This will help to keep your project clearly arranged, but you are free to place to place them outside the tree as well. This will help to keep your project clearly arranged:
The groups are hierarchical: all visibility or enabled/disabled changes affect a group's children.
...