Percolation changed a bit coming from 2.4 to 5.2. In 2.4 we had the opportunity to filter the percolators that were used before the percolation actually took place (see Additional supported query string options under Percolator API in 2.4).
In the 5.2 Percolator Query documentation I can't seem to find a way of filtering the percolators first.
I think it's probably done with some clever combination of other filter but I can't seem to find out how to do it. Any tips?