Im a bit confused when you say
so a definition file can contain a list of notes, with labels… then you assign it to a track
you also need to turn on SETTINGS > MISC > LOAD DEFINITION = FILTER NOTE
you would then only define the notes that you are interested in (*)
(e.g. Nord Drum P3 definition file)
this is described in the manual
this means you only get the notes listed that you have defined on that track.
… I don’t see where ‘current section of track’ comes into it?
another approach Ive used on synths, is just to delete all the presets Im not using… or group all my favourites together 
sorry, I don’t know the specifics of your rompler, so not really easy to suggest ideas.
… the way we ‘interface’ with every synth, is always somewhat different, depending on feature set/capabilities of the instrument.
(*) Im assuming you are using a note to trigger certain sounds on your sampler.