Replies when subject is wiped

When someone replies to a message and the subject (ticket number) is
wiped, is there a way (either in the 2.0.15 I am using now, or in
the one in the CVS tree) for RT to find the ticket number that a user
reply goes to by examining the Message-ID’s in the “References” header
and seeing where those references belong and add it to that ticket
number as correspond?

I hope what I’m looking for makes sense…