Thanks for the reply.
But atleast, Shopify can provide us an option to add some optional parameters when redirecting user for login and they should be sent back to us. That way, we can send some identifications for the server and client on that server (our system allows more than one clients available on one server and each client can have multiple company, and one of these company is requesting to login with shopify).
If we can send some optional parameters which will be returned back, then we can setup a centralized service to redirect to the proper location. Otherwise, it is hard to maintain redirect information.
thanks