I'm afraid I am not involved enough to know all the details. My point was more along the line that, despite this fierce rivalry there are occasions when both sets of supporters come together with a common goal, and all differences are put aside.
Liked the detail. I feel mention should be made of the REMF though. The platform where rivalries are put aside (sort of) at least one evening a year. Coming soon, to the Dripping Pan. Woodingdean Gull or Uncle Spielberg could provide the details better than myself.