Find POIs passed along route

I would like to add a list of POIs as additional nodes (or alternatively flag existing nodes in some fashion). I would then like to take a route given as a (possibly sparse) collection of points and use Graphhopper to return a list of the “POI nodes” which have been passed through by the most likely journey.

This feels like it should be possible but not sure where to start. I’m not expecting to be able to do this via the API and have already got some working map matching code written.

Any help much appreciated.