Cross-channel Source Groups used to take two tabs to build. Now you fix an unmatched field, while grouping the data.
You usually spot the gap at the worst moment. You've added the second integration to the group, and its Engagements aren't mapped to the unified metric the first one uses, so that channel's numbers don't land in the group. Fixing it meant leaving the builder, opening Organize, finding the field, adding the mapping, then coming back and picking up where you left off.
Now every field in the builder has a pencil on hover, in the unified column and in each channel's column. Click it, add the missing integration, save, and the group updates in place. One tab, one pass, nothing to rebuild.
Try it and let us know if it made your life easier.