Grudge matches not working.

I have been simulating an OHL season with control of every team and am about 2/3 of the way finished the season. I have not gotten a single grudge match for any team at all. Im wondering if its due to me having every team selected or that grudge matches only happen for nhl teams? In the deep dive they said the season mode was available for grudge matches so i am confused why im not getting any. Can someone help explaining this?