Node-red http response join of multiple sends

Question

I am using an http request node to send a request of all bacnet objects on a device, then with those many responses, resending a read request to the device with 15 at a time. If I do all at once it throws an error, 15 is a random number I chose to send...

Afterwards I want to join them all into a single response, but not knowing the number of responses and not being able to manipulate the bacnet read node to join responses, how can I join these all together?

I have basically 5-20 sets of responses coming out of a preconfigured (and un-editable) node, that need to be somehow joined into a single response to be sent to my http response node.