It will not affect the atmosphere of the derby for sure ;) There is one very heated derby here in my region too, between my hometown club of SFC Opava and our regional rivals Banik Ostrava. We haven´t met for years though as my club has been in the second league lately while Ostrava plays the first league. However, the B Team of Ostrava advanced to the same league where Opava is and in a month or so, there will be the game between SFC Opava and Banik Ostrava B but from the perspective of the fans, it will be as heated and violent as always :D It´s the fans who create the atmosphere, not the players ;)