Does an office with a Goyishe owner but has many Jewish employees, some even with their own offices, need a Mezuza?

 

The Jewish employees who have their own offices, should put up a Mezuza without a Bracha. For the other offices, one should  not put up Mezuzos.
One should also put a Mezuzah on the main entrance or doorways that lead into the Jewish offices, but only if there is no concern regarding the respect of the Mezuzos.

See here for more information.

 

Sources:

יורה דעה רפו, א בהגהה

וע”ע מדין חנויות שבשווקים.