各司其职
gè​sī​qí​zhí

to each perform their own duties

  1. 各 gè determiner
    each
    each; every; all the various; used to refer to every individual member of a group; often used with people or places
  2. 司 sī noun
    to take charge of
    (bound form) to take charge of; to manage; to attend to; to operate
  3. 其 qí pronoun
    [third-person possessive]
    his; her; its; their; refers back to a person or thing mentioned previously
  4. 职 職 zhí noun
    duty
    (bound form) duty; post; office; official position