Your school may want to limit communication between member groups, example students should not be able to send a mail to the proprietor and this can be done as follows:
Click on “Portal Setting” Menu
Click on ”Access”
Click on “Mail Restriction”. Mail Restriction can be from Student to Manager, Parent to Manager and Teachers to Manage.
Click on the member's sector you want to restrict. You can select more than one managers by “Hold down Shift and the Select the managers”
Click “Update Setting” to save changes made.