Merging maildirs

I tend to use several machines. But I want all my mail somewhere so I can search it with mairix for example. On my laptop I have sent-mail-07-2003/ maildir. I also have the same maildir on my home machine bilbo, however with different mails. I want to merge those two folders at some point, without overwriting or losing mails. After copying sent-mail-07-2003/ from my laptop across to bilbo’s /tmp, I proceeded to:

cd /tmp

cp -R --preserve --reply=no sent-mail-07-2003 ~/Mail/sent-mail/

And it seems to work.=)