If you are a kindergarten administrator and you want to modify the groups a teacher has access to, you must go to the "Management" module followed by the sub-category "Staff Management". After we have found the teacher to whom we want to modify the group acces, click on the "Actions" button next to it, followed by the "Edit" button.
In the central part, above, are the groups the teacher has acces to. By pressing the "X" button next to the group we delete it, but by clicking in the group field we can add another group. Dont forget to hit "Save" button when you are done with the editing.