If the form is placed via an Online Form WebPart (not widget), you can use a macro for the value of the Form Name.
You would then use the macro engine to get the workflow, something like:
{% if(CMSContext.CurrentDocument.WorkflowStep.CodeName == "Step1") { return "FormStep1"; } |(identity)GlobalAdministrator%}
This way the Form loaded will depend on the workflow step. Just be careful the workflow step doesn't change between page cycles (like you submit in Step1, and during the submission it changes to Step 2 on the workflow).