Sharing a massive distributed merge

We have two codelines that diverged quite a while back, and we are now bringing them back together. More than 800 files are in conflict, but it is very possible that the automatic non-conflicting merge is not correcting. This means thousands of files need to be examined.

Git doesn't support distribution of a merge (although that would be extraordinarily cool), so the next best thing seemed to be force adding all files with conflict markers and then committing the merge. We then publish the conflicting branch and have each person fix their files. Given that the conflict markers are already in place, they can't use their favorite graphical merge tool.

What I want to be able to do is have each person perform the merge locally, stage only the files they care about in that session, reset all other files, and commit as a regular commit, not a merge commit. The user can take advantage of whatever tools they want in the in progress merge. When everyone has finished this process, we run git merge and keep our local changes.

I have had no success in doing the above. Is there a fancy way to pull this off with Git?

Thanks.

Josh