Add a new filter option "Mark thread as" read

I use filters a lot, in order to classify my incoming mails. Particurarly, I use filter to classify Redmine incoming mails (mail about ticket progress).

These mails are well handled as threads. Typical case is that the last mail in a thread is an update of this ticket to a Closed state. I already detect this state update with a filter. The best rule I can apply to this filter is "Mark this mail as " read. What I would like is a new filter rule, allowing to mark the whole thread as read.

I understand that thread is a high level view of mails, but maybe someone could think on a smart way to do that.

Regards,

Jérôme