moving whole directories with contents in the folder view (left) panel?

Greetings all;

I have for the time being, given up on the idea of fetching my mail with 
fetchmail as I have finally got it working to rx from the dovecot server at my 
ISP.

But I've a folder list that is about 22" high. as there is 3 "root" locations 
for mail at one point or another.

What I really need is a way tp pick up a directory in an account list, and 
drag and drop it into the account listing corresponding to "IMAP Account 2", 
and auto move everything into that tree. Sure, I could do it one msg at a 
time, But there are about 13Gb of them.

mc could do that, but would that crash kmail?

Thank you for any advice.

Cheers, Gene