We added a reference qualifier (BackfillAssignmentGroup(); ) in the assignment group field to default to the users Group when they create an incident which works great if that person belongs to one group. We have users that may belong to multiple groups and we can't figure out what logic ServiceNow uses to determine which group to back fill the assignment group when you belong to multiple groups. Some of our users are requesting it to default to a specific group since that is where they do most of their work. Their secondary group may only receive a few incidents a year.
Thanks
Rob