Thank you very much! It does work exactly as i imagined. i did not expect the FE author to nitice this anyway, this is my final edit: CATEGORY { name = Filter by Function type = stock value = replace SUBCATEGORIES { list = 19,Life Support } } SUBCATEGORY { name = Life Support icon = Lifesupport FILTER { CHECK { type = folder value = ThunderAerospace } } } @SUBCATEGORY[Utility] { @FILTER,* { CHECK { type = check invert = true CHECK { type = path value = ThunderAerospace } } } } TAC's parts are now no longer in the utility folder, but in a seperat one similar to your additions (e.g. Airintake, Langing Gear, ect.) again, thank you very much