This is how to edit a color group in Adobe Illustrator.
When we want to create a color group, we come over to our swatches panel. Same way these folders are we would click a folder, name it-- let's say we name is "something," and now we have a new folder here.
So we have a new color group. There are no colors in it currently, but we can add any colors we want. By doing this, we continue to add more colors to the actual color group.
Now, if we wanted to remove some of theses colors, let's say I wanted to remove the green from this because we clearly have enough green in our groups already, all I do is I click that swatch and in the swatches panel at the bottom you'll note there's a delete swatch button.
We click that. It will ask us to confirm. Click yes. Now that swatch is gone.
If we want to add to that color group we just select that color group and we click the new swatch and then we can actually select a new swatch that will automatically be added to that color group itself.
And that is how you edit color groups in Adobe Illustrator.