CX app invoke response: can status only be returned at the invocationId level?

We have a CX app being used in Responsys programs. We are adding a response to the invoke request, but do not see an option to return a result for individual contacts in that invoke. For example, our app receives a payload of up to 10,000 contacts in the request. Those 10,000 contacts may be processed at different times, so we would like to properly report back to responsys when the contact(s) have completed processing so they can move to the next step in the program. The docs look like we can only return a response