svn merge without working copy?

[Wade Preston Shearer]

The svn merge command says that it "appl[ies] the differences between two sources to a working copy path." I would like to:

1. check a few files into trunk resulting in a revision

2. merge the difference between that revision and the latest revision of a branch without a working copy of that branch


Is that possible? or is the only way to have a working copy of that branch that I merge them into and then commit them?