Keep in mind you can issue different job numbers but still associate the different jobs as part of a 'group'. For more info on this feature see the help topic: Service Job Groups
Otherwise, to do exactly what you want you would need to add a question to the service job form, and then add a rule to the body of the form that filters on the stage. For example, if your question is "Include Stages Equal or Higher Than" and this assigned the user's answer to the variable Answer3, then the rule would take the form of:
Val(SMstock->Stage) >= Val(Answer3)
*Attach the rule to the body of the form that lists the items you want to filter.