Gnus split methods "except" rule?

**EDIT** Trying posting this again since apparently the reddit bots took it down as spam last time, with no explanation of why. Using Gnus to handle my emails I use `nnmail-split-methods` to sort my mail into groups, and I also have `nnmail-crosspost t` so that I get threads that include my sent messages (at least on Google servers). The trouble I have is that there are some auto-emails generated by an external watcher system that writes to an address that I already hav ematching another group. Because cross-posting is enabled, it gets filed in BOTH the group I have just for those emails, and also in my other primary group for that address. What I want is a rule that says: "Split to my `TO: GROUP` UNLESS from the certain address" (ie don't duplicate those particular ones). Does anyone know how to do this?

you will have much better luck asking in the Gnus mailing lists.

I don't use it, but the 'Fancy Mail Splitting' section of the Gnus manual has an example right at the top where some mails are excluded (using `|`) from cross-posting (which uses `&`). Btw, you can also try the newer `nnselect` method for viewing sent mails in the same thread for any backends (ie not just Google).