On the glance tab, show a column for the human player's attitude towards the AIs. It would have just a single attitude icon per AI, and clicking it would cycle through the attitudes. Ctrl- or shift-click could go the other way, but it should wrap so people don't have to know about it.
The attitudes would be saved of course, and whenever the screen is opened, it should start by sorting the AIs horizontally and vertically from friend-to-foe or vice versa (option). Sorting is already a feature by clicking leaderheads, so this isn't so tough.
The motivation is so you can organize that insane tab more cleanly and make planning your friendships easier.