If you need to edit one clip within the clip group, you should ungroup the clip group, edit the clip, and then choose Regroup. And if I use that command here, you'll see that the group gets ungrouped. You can also choose to ungroup a group: Command+Option+U on a Mac or Ctrl+Alt+U in Windows.
To make a clip group on a Mac, you can press Command+Option+G on a PC it's Ctrl+Alt+G. Now, of course there are key commands for clip groups. I'm going to go and move these two tracks closer to each other and highlight these two, create a clip group, and now we have this icon to indicate a MIDI clip group. If I move this track, now they're together and we have this new icon that shows that this is purely an audio clip group. And this icon shows that the clip group is split, so that means that there are tracks in between the parts of this clip group. If I make a clip group with just audio files, like I'll do here, Clip > Group, now we have a different icon. Now, this particular clip group contains both audio and MIDI clips, and that's indicated by this little icon right down here at the bottom. So I'm going to undo that and then go to GRID mode. It's a great technique to test out different song arrangement ideas. So doing this, I can check to see what this would sound like with two verses in a row, as opposed to just one. If I go up to Shuffle mode and then go to Edit > Duplicate, it makes a copy of that clip group and pushes all the rest of these clips over to the right. So I'm going to use clip groups as an arrangement tool. Now, let's say that this new clip group comprises one whole verse of a song. So if I undo this and actually add in some more clip area, go back up to Clip > Group, even some of the stuff that wasn't separated is now included in this clip group. Now, it doesn't really matter if the clip underneath the highlighted area is actually separated or not the clip group will actually include whatever you highlight. I'm just going to double-click on this clip and Shift+Click on these, and now I can simply go to Clip > Group, and it creates this clip group right here. You can simply highlight a bunch of different clips, and I'm going to go ahead and do that right now. A clip group is a combination of several audio and/or MIDI clips that act like a single clip.
One of the features of Pro Tools that makes large-scale editing and song form arrangements so easy is clip groups.