Transfer on spouse ground in banks

Dear Sir, I am working in nationalised bank and my spouse is working in another nationalised bank in Jaipur till 23 July 2018 . After my transfer to Bhopal , my wife and a year old son is alone in Jaipur. Jaipur is not my native nor of my in laws. I am married in Mar 2016 and i was completing about 3 years in Jaipur in Nov16 after transfer from Ahmedabad so I request to get my transfer to Lucknow as it was nearby Allhabad (my wife place). I am a specialist officer hence can be posted in zonal offices which are generaly in metro cities. I could not get transfer due to quoting of some technicnal reasons that some handicaped person will be posted in lucknow and a fit person is posted there.I have asked my wife to take transfer on spouse basis to Jaipur and she joined in Aug 16 in Jaipur office. In June 2017 , I got transfer order to Bhopal, even I have requested to extend one more term as my wife is transferred here and getting again tranfer before term is not possible .My wife is about to deliver in June , with many request i am retained in Jaipur for 1 year. In 2018 I again got transffered to Bhopal and this time I joined . My wife also put request for transfer to Bhopal on spouse ground. But the request is rejected quoting the reason that your term of 3 years is not complete .Your cannot put request after Sept 2019.I and my wife talked to unions also which are saying that request transfer on sposue groud is permissible one time in service period . Kindly let me know is there any legal provision that she could get transfer as she is alone in jaipur with our one year son. It is difficult to manage her alone along with service in Jaipur.