Simplify the following text for a Grade 15 native English-speaking person.
Original: The group is treated either as a single family , Alcedinidae , or as a suborder Alcedines containing three families , Alcedinidae ( river kingfishers ) , Halcyonidae ( tree kingfishers ) , and Cerylidae ( water kingfishers ) .
Simplified: This group contains three families ; Alcedinidae ( river kingfishers ) , Halcyonidae ( tree kingfishers ) , and Cerylidae ( water kingfishers ) .