Adress change process

Me and my brother are having different partnership firms, we were having our own business premises which we have to sold due to some reasons, and now we have shifted to a new premises which we are sharing and it is rented and owner of the premises habe made a rent agreement and have also given permission to share the same premises to use for other partnership firm.
We applied to GST for change of address formalities on new address but, GST authorities are saying that they will not transfer our registration number to new premises as it is shared and two different partnership firms can not run business at same shared business premises.
What is the solution to this scenario.
Please give your valuable advise to solve the issue.
Regards.