I assume you're using InfoPath and SharePoint 2010. I assume a button or something updates a field called Form Stage.
Publish your InfoPath form and promote your required columns i.e. Form Stage. If you haven't already create an "Admin view", so that if required you can change/alter the Form Stage field. - Great for testing/troubleshoot. See point below.
Natively you can't "loop" within a SP workflow. You can to an extent get around this with an Else If and Wait statement.
In your workflow you would just use Wait Until X equals X. Then email X.
You might need to promote the columns of "people" you want emailed or use SharePoint groups.