Is it possible to have more "basic" options to the usermin filtering options? For example it currently will match on an exact match header, but won't do a "contains" type match, or "starts with" or "ends with" or anything similar.
I'd like to add some more header types (such as "Reply-To") as default.
Also it's not possible to do multiple choice matches such as match on email address AND header value.
An example of something I've done before that worked well is the sieve filtering plugin for squirrelmail. It had lots of flexiblity in terms of choices and outputs.