I am trying to run the plastics simulation with a multi cavity mold that has a runner and cooling system.

I have modeled in a cavity, runner, gate, and the cooling system, but SolidWorks is unable to identify them as separate cavities when I try to run the solid mesh. I'm unsure if I modeled it incorrectly or if I missed a step in the modeling that would help.

The Blue is the cooling system, the red is the runner and gate, the rest is the cavity

Any help is appreciated, thanks.