@SravyaK5 - Do you have authentication enabled in your service package? If you enable basic authentication also you can pass different user identifier for different markets while invoking the service. At runtime the service activity will be executed using the access group of the operator id which is passed while invoking the service.
Another approach will be to change the accessgroup in the service activity. You can have an initial step to switch the access group. You can find the relevant code for doing this in RedirectandRun activity.