One issue I've heard about a lot recently has been how to group players to get the best out of them as a team yet still develop them individually. to me there's not just one way to group hitters there's many great ways to group hitters. But deciding to tackle this problem in the first place you probably already have a general idea of who your hitters are and how they need to be grouped. Taking a systematic approach to grouping these hitters and not just going through the lineup is going to greatly change how you plan your practices as well. By giving your hitters depending on their swing type, their approach at the plate, their strengths, or by their position groups will open up a lot of opportunities to change practices to get more out of them.
The actual grouping of hitters to me personally comes down to what you want to get out of them. If you're a playoff contender and looking to go deep in playoffs as an expectation in this part of the season then grouping them by their strengths will greatly improve the confidence of the individual hitter. Seeing other guys be successful that are in the lineup with the same talents that you have produces competition within those groups and also reaffirms that as your strength. As a leadoff guy whose job is to work pitchers and have a high on base percentage while still being able to do damage with the bat I don't want to be around our 3 and 4 hole hitters who's primary expectation is to drive runners in on a consistent basis. 3 and 4 whole hitters typically in a lineup are going to be some of your stronger hitters that are going to put balls out of the park. As a leadoff hitter I might have the capability to do that, but that's not what my expectation is. Instead my expectation is to drive balls in the gap find ways to get on base and be able to read both a pitcher and an umpire. My lead off group would probably be something more like 1,2,7,8,9 hole guys, who’s mentality and results will typically be about the same (although hopefully your 1&2 are higher OBP guys. Where as my power hitting group guys that I expect to be able to drive the ball consistently and put it out of the park would be my 3,4,5,6 hole hitters. An even further group would be dividing 1,2, and 9 Hole hitters together, 3,4,5 hole guys together, and then 6,7,8, guys together. The justification of this is to get guys who need to find success in different ways grouped together.
Now if you're a team that is going to consistently have to develop hitters to me it's imperative that you both measure and assess them before placing them in groups whether that's with a blast motion sensor, radar gun and exit velocity or simply where they’re most consistent as far as hitting the ball. By using metrics that you can test and putting your players in those groups based off of those metrics You hope to push those ideas even further. Stations will be easier to set up drills will be easier to set up, and players will be able to help coach each other through drills and stations because they're working towards a common goal. Players will push each other, and continue to progress by the competition around them progressing. By having groups based off of common goals you can build that unity within your team.
The last situation I mentioned is if you are having a competition, or players are battling it out for starting positions. It would be beneficial to have those players in the same groups. Many players need competition in their practices, and placing two players who are competing for a position will let you see these athletes side by side, and will show them what they are competing against. Athletes are driven by each other, and having athletes that are in a true battle with each other side by side will show those athletes exactly what the competition is, and how much harder they need to work in order to keep, or earn that starting role. It will also let you judge these hitters back to back and compare more objectively. With your batting practice set up with these hitters next to each other it will also show you which hitter will handle the pressure of competition with the guy next to them, and which one may falter.
Creating groups that push your team towards common goals based off of the guidelines and rules that you set will greatly enhance your practices, You're in game experiences, but most importantly the culture that your team is creating. By using any systematic type approach that you feel you can justify with other coaches (to me the best way to test an idea is to throw it at as many minds as possible, and have them poke holes in it) you will be solidifying your team's chemistry in line with your goals. Planning practices can drastically change your goal for the day, as well as the athletes perception of the team and their role within it. Plan practices to get what you want most, and plan with these groups that you set to create opportunity, culture, and build competition through every stage of practice.