Look in front of you
In a group, you sometimes do things better when you are not too social :-).
Most people look at each other as they talk. In our culture, we are accustomed to that and for many that is the proper way. However, in some situations it is not practical or sensible. For example, in the car. There, the driver should keep his eyes on the road, and not to look at his passenger. In a group ride, cyclists tend to talk a lot, and many look at each other.
Even the pro’s look in front of them when talking to one another
When riding in a group, it is safer to look in front of you, and not to the one you’re talking to. Talking is done from mouth to ear. The eyes remain focused on the road in front.
Just like when you do not have your hands at the brakes, looking at your neighbor, i.e. not looking at the road, adds a delay to your responses. It may not necessarily lead to an accident, but the behavior of the group as a whole will be much more erratic and your group will ride in a less compact formation.
Talking to your neighbor and still looking at the road is easier said than done. You will have to practice. And coach each other. Especially those who ride behind a pair that look at each other constantly: you kindly interfere. Tell them they need to look forward.