In my PMP implementation, we have several different organizations and some of them (not all) have their own domain controllers and domain names to authenticate.

One of these organizations decided to fold into the main organization and now their users are authenticating against the AD domain name of the main org. But, since they have password sharing enabled within the organization, they still need to stay under the same org umbrella.

I just need to find a way to change the AD Domain name, against which the users need to authenticate. How can I do this ?

I have submitted a ticket a month ago but it was closed and the last answer was useless, suggesting local authentication. This is not what I want.