Thank you Ohrenkino,
my solution is then a cross between your reminder of the filter function and the .exe from Dano (topic Dano - Splitter)
I filter my whole database then export with an adapted export file (it's a loop from folder with an inside loop from %origyear% or %Itunepurchasedate% depending on the %_extension%... fuuuuuuuuun 
)
After that, the result is splitted in multiple playlist (m3u in my case).
very nice !
Thank you Ohrenkino and Dano