We have a single group for editors and want to setup a Workflow in which any one from the editors Group can review & approve the change except the one who actually did the change.
For the first part, it's easy. Just set the group as the next performer in the workflow activity definition.
For the second part, you'll need code. Likely the best place is an event on activity start, where you check if:
- This is the review activity
- The user performing the start is not the same as the previous performer
If the user is the same as the previous performer, throw an exception telling them that they can't do this step - this will also stop the activity from starting and will remain in the queue for anyone else in the group to start.