How to distinguish Normal employee and Agent while raising a service request through groovy script

Summary:

We have a requirement, Service Request details entered by employee should n't be editable by Agent. We are able to achieve this through a groovy script as below, however, when the agent himself raises a request as employee, he is restricted to raise his own service request. Is there a way to distinguish a agent from a normal employee?

Content (required):

Is there a way to distinguish an agent from a normal employee? Need to add this in our groovy script, so that we can conditionally allow update to request details not being allowed an edit by anyone once submitted.