Would it be a group mechanic as the OP talks about or something for the individual? Maybe both? You could tie it into fate points. If a single character wanted to, they could spend a fate point and "I remember when..." and get a bonus towards whatever roll is at hand. For the group, as long as they have a shared history (either through background or game play), those players that choose to could pool those points together for a higher bonus to the task at hand. Could help encourage teamwork.
