cherry-pick/rebase question

Say I have the following linear set of commits on master:

A---B---C---D---E---F---G master

And I realize that I've intermixed two topics such that I want to move commits B and E-G to their own branch. So my result should be:

A---C'---D' master
 \
  B'---E'---F'---G' topic

What's the best way to do it?

I read the rebase and cherry-pick man pages, found myself confused, tried rebase a few different ways, failed, and ended up doing what I needed with format-patch and am. (Extract B-G with format-patch, reset master to A, create topic branch, apply B,E,F,G to topic with am, similarly apply C,D to master with am.)

Thanks,

j.