For group email, no, not really. Normal email has several baked-in protections that make this kind of context injection / split-view tomfoolery a lot harder to pull off. You have to go back decades to the very early days of email before you get to a situation like we have now with NIP-17 groups. There are some workarounds, most having to do with every client trying to keep a spying eye on every other client in some George Orwell 1984 JOSN dystopia, but they all end up in this uncanny valley between NIP04 and MLS, too hard for people to understand and not enough payback for being too hard to understand. You could do nostr email with NIP04++ DMs though.