This is entirely upto the organisation concerned.
However, I have come across some instances where married couples have been asked to search for other positions - usually the one who is most valued by the orgn is asked to stay, and the other asked to look for an alternate appointment.
This is for two reasons - first, if they are both in the same function/dept., when promotions occur, one may have to report to the other, and this could cause crisis situations; also, disputes may spill into the home front also, making life pretty uncomfortable; second, even if they are in different functional areas, once again if one is on a more senior footing, the same discomforts arise. Also, sometimes colleagues resent the situation, feeling that the more senior individual is more lenient when the spouse is involved, particularly if they are both in the same function/dept..
There are times when one is asked to transfer to a sister concern in the same city, without affecting job function or seniority. This is a good strategy but very few orgns. are in a position to follow this.
However, I have also come across a few cases where the couple is in the same orgn. but in different functions, and yet a very comfortable balance has been achieved.
In such cases, the orgn. steps in where reimbursements such as leave travel and medical reimbursements are concerned; for instance, if leave travel covers children and dependent parents as well, then the more senior spouse, say, the husband, covers himself and the children and his own dependent parents, and the wife covers herself and her own dependent parents. This prevents reimbursement covers from being doubled.
Where both are entitled to company housing and company cars, then only one house is provided, and one car, unless hours of work and usage on company work necessitate separate cars.
However, all the above are on an orgn. to orgn. basis, and on a case to case basis, and the couple cannot make excess claims.
I hope this has thrown some light on such cases. I'd like to hear from others also.
Jeroo