SW SetGroup helps to manage your registered user by scanning their e-mail address and push them to or remove them from special ACL groups. This is accomplished by regular expressions.
SW SetGroup is used for example in the student council of ETEC KIT. There, each student has an e-mail address ending in either stud.uni-karlsruhe.de or student.kit.edu. All e-mail addresses that match this pattern will automatically be added to the student group and get special permission on the site.