<prompt> Translate the following text to EnglishUsimamizi wa Huduma za Posta wa kuingia katika Mikataba ya Kiwango na Huduma ya Mikataba na Wateja wa Binafsi au Vikundi vya Wateja kwa Huduma za Huduma  <response>: POSTAL SERVICE AUTHORITY TO ENTER INTO NEGOTIATED RATE AND SERVICE AGREEMENTS WITH INDIVIDUAL CUSTOMERS OR GROUPS OF CUSTOMERS TO PROVIDE SERVICES 