Parameter to specify version system

I have some cross-versioning system projects, e.g. with both a local `.git` and a `.svn` in some upper directory.
Right now I usually temporarily rename `.git` to `.git2` or something when I want to commit to SVN, but it could make sense a parameter like `commit-partial --svn` to force searching only for that.
(same goes for being capable to commit into git when `.svn` is at the same level)