So. I have a project I'm currently working on in which there are a number of characters who are connected to each other by various friendships/familial relationships, although they don't all know each other. For various reasons, all the characters must talk to each other in a web chat format in order to plan a project.
However, one of the characters (S) is unwilling to join this chat because it would mean he had to interact with a particular member of the group (L) who he holds a grudge against. Though I do not intend to reveal it at this point in the story, the grudge is due to L permanently disfiguring S in a confrontation between them.
Before his introduction, S is referred to by the other characters in relation to this 'incident' and the fact he has a grudge against L is mentioned, but what actually happened is not described.
I'd like to be able to show that S has good reason to hate L, and isn't just being resentful for nothing, without giving too many details about the 'incident', which I intend to have brought up when S abd L meet in person later in the story.
Are there any methods I can use to do this without being infuriatingly vague? Thanks for any suggestions!