Anyway to define and take an action on "Keep Artifacts Forever"

[Greg Smith]

Hi,

I would like to take an action (kick off a downstream job) on any artifacts that marked as "Keep Forever"

I would usually use the Promotion plugin for this, but this will be a mix of Multibranch Pipeline jobs and normal jobs -- and the Promotion plugin does not yet work with Pipeline. 

Does anyone have any ideas how I might be able to do this?  I am really missing the Promotion plugin with Pipeline jobs...

Cheers,
Greg