Create a branch from any commit, not just another branch

We have a workflow where we pull request from a "develop" branch to a "release" branch for daily and weekly builds. Infrequently, but often enough to be annoying, the tip of trip has an issue and we would like to create pull request from an earlier commit.

Similarly, when there is a merge conflict, I would like to merge an earlier commit which would be "conflict free", then merge the conflicting commit and push for a code review. This narrows the scope of the code review to the conflicting files.

Creating the branches for this can be done from the command line, but it would be more convenient if it was done in stash.