How to merge groups
If you need to combine groups, you can add one group into the other in bulk to merge them. To do that, you’ll first need to pull up one of the groups that you’d like to combine. From there, you can tick the “Select all” box in the lower left corner of the page to select all of the records in that particular group.
You can then select “Add to a group” in the bar that appears above that, and then select the name of the other group. This will add everyone in the selected group into the other group, thereby combining the group members. If you want to get rid of the original group after they’ve been combined, you can do so on the Manage groups page.