I knew the general idea of -tachi, as explained e.g. here: "Hey Bro!" how to call out friends
However in one ranobe I read the following situation. Assume there is a supervisor Asahi and 2 employees Kimi and Mashi of same "grade" sitting at the same table. And Asahi addresses both of them ("you two"/"both of you") using "Kimi-tachi".
Isn't such a call-out insulting for Mashi? I mean, the close translation would be "Kimi and the other one", "Kimi's group", etc, correct? But since Kimi and Mashi are of the same "level" that should not be bound to a name of one of them, I think. Please explain.
EDIT: I chose random names from random manga, in order to not expose the source, not thinking that kimi happens to be a personal pronoun. My bad, gomenosai. The original text had different names, and there was clearly a case of addressing a group of people using the name of one of them +tachi. Can you please explain this situation?