Hi Ryan,
I am not affiliated with GrowthBook, and I don't know if we can answer each other questions here, but here is what you can do.
you can implement your own splitting logic and add a query in GB to for experiment assignment and then instead of creating an experiment from a feature on GB, you go to experiment -> Add Experiment -> import existing experiment, then you can see the results on GB.
Keep in mind that splitting by states is not a proper AB testing.