preferred bowls and/or preferred/disfavored *opponents* to the conferences. The SEC will do its best to accommodate their requests, and if MU was adamant about not playing KU then the SEC would not force them to.
https://www.actionnetwork.com/ncaaf/updated-bowl-game-projections-week-14-brett-mcmurphy-college-football-predictions
Schools provide their bowl preferences and the conferences, bowls and schools usually come to an agreement whenever possible. It’s not unusual for schools to request not playing certain opponents in the postseason, sources said.
There's a source for you (but it's also common knowledge and common sense).