Similar multi-poller use case that overlaps--combine NCM reports as one somehow. Since NCM can make files on filesystem, my team used to move Down Nodes reports from our filesystem to a Linux server. Now it's multiple files on multiple servers. Unfortunately what I see as the easy solution (Linux server retrieves Down Nodes web page via curl) fails since the Linux server is not accepting our certificate. I only control the application and to some extent the Windows servers it lives on.
I understand that the poller-bound behavior is working as designed since changes in NCM 7.3. And I know of a few other ways to turn a web page into a file on the file system. Unfortunately they all require things I can't implement (for example PowerShell v3).
Note that getting a report on the filesystem would be even better in the context of NPM. We were just using NCM since it could create files on filesystems. But not all of our devices are NCM licensed and we wanted to show any down node (servers included--and we tend not to put them in NCM since there is no config management expectation on servers).