I have a big issue with Thunderbird, I need to process a lot of emails coming from request tracking system.

Since only few of those apply to me personally, I tag these threads with appropriate tags.

The issue now is that I would like to filter out threads, that do apply to me and those that I haven't tagged yet.

I'm unable to do this, because new emails keep arriving into the already existing threads, and of course, these new emails don't get the tags.

Basically I would need some sort of filtering rule, that would apply not to a specific message, but the master message in the thread.

Is there some possibility to create such filters, or is there some other facility, that would allow me to do the same? Tags are great, since they are actually saved into the messages and correctly sync across multiple machines when using IMAP.