Hi Jai,
As Chris&Matt said there is not an easy solution, but my suggestion is to set up the IdM authorization to be against AD, so to log in IdM the users should use their AD credentials. Then if the users want they can reset their password by using the standard Password Reset workflow(the password will be reset in all of the systems). In order to reset the password partially, you should do some custom extension of the standard workflow.
BR,
Simona