Groups are created using the Create() method of the GroupCol object (project.Groups). After you create the group you will need to apply materials (group.VariableMaterial), variable bounds (group.VariableBound), concepts (group.Option), and assign components (group.ComponentMembership).
-Ryan
bpfCorrugatedStiffenedPanelFamily = 3;
groupId = 106;
familyId = bpfCorrugatedStiffenedPanelFamily;
index = project.Groups.Create(groupId, familyId);
group = get(project.Groups, 'Item', index);
disp(group.GroupName)