Multiple targets for parameterOverrides

[CraigLager]

CloudFormation allows us to override parameters on stack instances: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/stackinstances-override.html#stackinstances-override-console

cdk-stacksets only allows one target property, which contains the parameterOverrides property. This means I can't have a StackSet which targets different accounts with different parameters.

Also, I'm struggling to find how to actually use parameterOverrides in a StackSetStack