I am running a notebook that makes multiple plots.  I define a function and then I want to plot that function for different choices of parameters, using `RegionPlot`.  Given the complexity of the function (which is why I'm not copying the code here), it takes ~2 hours to make each plot, and I need about 20 separate plots.  Since the plots are completely independent of each other, this seems like the sort of thing that should be parallelized.  This is my goal.

I've figured out how to launch the subkernels and how to move the definition of the function to the subkernels using `DistributeDefinitions`.  (Sorry if that's not quite the right terminology.)  I've been trying to use the subkernels like this (pseudo-code):

    ParallelSubmit[RegionPlot[* code with function[x,y,z] here *]]

    ParallelSubmit[RegionPlot[* code with function[a,b,c] here *]];

However, it seems to me that the `ParallelSubmit` doesn't actually get evaluated until `WaitAll` is called, and I can only find a way to apply `WaitAll` to one of the two instances above; hence, I still end up evaluating them sequentially, which is not what I wanted.

So my question is this: what is the easiest way to parallelize the production of plots (for different parameters) in *Mathematica*?

Thank you in advance for all your help!

It occurred to me that perhaps an example will help to clarify:

    F[x_,y_z_]=x^2+y^2+z^2;
    DistributeDefinitions[''Global'''];

      (* I do have a back tick on the Mathematica code but I'm revising this on my phone which 
    can't type one. *)
    ParallelSubmit[RegionPlot[F[x,y,1]>5,{x,-10,10},{y,-10,10}]];
    ParallelSubmit[RegionPlot[F[x,y,2]>5,{x,-10,10},{y,-10,10}]];

How can I run `WaitAll` so both `ParallelSubmits` evaluate at the same time?