Svn and git rest

We've got two teams: internal team in the office behind a proxy using internal svn; external team out in the open internet using git and wanting to collaborate but not being able to access the internal svn. Internal team must remain on svn, office network can't allow external access.

The question: how can the office team relay their svn changes to external team's git repo and back from git repo into svn?

In the office we were quite successfully been using git svn so that all local development is on git with fetching and dcommitting from/to svn. But we can't quite figure out how to link a remote repo so we could do something like:

git checkout gitmaster
git merge svntrunk
git push
git checkout svntrunk
git svn fetch
git merge gitmaster
git svn dcommit

Git-svn is for a single user that what have an git interface to subversion, collaborating on a git-svn clone will eventually fail (i.e. git-svn uses reabse when fetching updates from subversion and uses current user as author when "pushing" commits back to subversion).

You may resolve the problem with a briding application such as SubGit, SmartGit or