Hi there,
My users (clients) seem unable to keep each e-mail thread focused on one thing so often one same message may refer to a couple tickets.
This means that we need to either:
a) move the transaction / message to another ticket
b) clone the transaction into another ticket
I saw Splitting off transactions as new tickets about cloning into new tickets, which I guess I’ll be able to find out how to modify into B) but, How about A)
marc
You could move the transaction in (a) into a new ticket and then use the standard RT tools to merge that into another existing ticket.
My users would kill me. This happens so many times a day that I have to find a way to make it a straightforward two click process. Like the thread linked above but adding a step to offer to clone into an existing ticket.
But I have to learn some Perl before!! 
just started Preface | Modern Perl, 4e
You’ll have trouble making it just a two click process, as your users will need to specify the ticket ID that they want the transaction merged into.