Dear Nagaraj,
The benefits of the contract employment are far more limited. Therefore, I doubt whether your wife can apply for a posting to a place where you are working. However, if you are a regular employee of the government, then you may put forth application for the transfer to a place that is near to your spouse's working place.
Since reasons for asking the transfer are personal, for submitting such application, there may not be a service rule defined. However, nothing wrong in putting up application. Give a try.
Thanks,
Dinesh Divekar