Pitch Groups allow you to organize your pitches and defensive plays to fit your team's needs. Your pitch groups can be organized by pitcher, certain pitches, defensive plays, etc.
A "pitch group" is where you store a group of pitches, defensive plays or any other applicable play. They allow you to organize your team calls in the best possible manner for your team. Pitch Groups can be found in the "Defense" tab on the bottom of your screen. You can create a new pitch group by clicking the (+) in the top right corner of the defense tab.