Hi Ravi,
I have gone through the question put in by you. Well as far as my view and experience is concerned i think a married couple should not work in a same office or same department reason being that there are so many issues that comes in front of you once both are working in same office or department. One of such important issues is....
1. Working for late hours is not possible for both, if one wants to leave then the other have to.
2. Productivity also gets affected like if husband falls ill wife stays to take care of her.
And besides these many other issues are there. Though there is no such legal rule that both cannot work, but generally companies donot favor husband and wife working together in same office or same department.
Well i also think that as far as decision regarding whom to say to leave, it solely depends upon the company either u can say both of them to leave or can change their departments if possible with different shifts incase its applicable to your department.
Thanks
Nitesh