Multi Cavities

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.

SolidworksPlastics And Mold Design