Confusion regarding multiple xframes and request.response

[eshtadc]

Hi there - I'm doing some proof of concept work with postal.js, postal.xframe, and postal.request-response. Overall this is amazing stuff and I really love how well structured it is. I'm running into a bit of a mental road-block figuring out how to handle multiple frames responding to the same request. It seems like a Promise.all() type of functionality needs to be used and probably could be in my implementation but I'd love any guidance as to where (pseudo-codeish or conceptually).

For example:
index.html sends a request on channel A
iframe1 and iframe2 are both listening for requests on channel A.
I want index.html to respond when all iframes have responded rather than when the first response is returned.