Get arrays from different stages

[rettenda]

I am using PDAL for loading and processing pointclouds into a python script. Hence I am not really using the writers and just reading the pipeline's array after applying the filters.
In this reply, it is stated, that it's possible to have multiple writers in a pipeline. But is it also possible to grab the arrays from mutliple stages of the pipeline when using the python extension? Or, during processing, to enforce storage of a apecific array?
Specifically, i am applying a range filter to the classification. And if the result has too few points, I would like to grab the array before filtering to continue processing with that.