Here are some things that this would make possible:
- Having a group of Unown that spell out a certain word (each letter is its own group of 1 with a 100% chance of getting picked).
- Having a group containing one male Pyroar, a few female Pyroar, and some Litleo (the male Pyroar spawns with a group of female Pyroar and a group of Litleo). This is, if I remember correctly, how prides of Pyroar and Litleo are typically comprised.
- Having a family of one male evolved Pokemon, one female evolved Pokemon, and some first stage "babies" spawn (one group of 1 of the opposite parent and one group of kids).
- Having a third stage Pokemon like Emboar spawn with some of the first stage and some of the second stage (one group of the first stage and one group of the second stage).
- Having a group of two Pokemon be closer to equally comprised of both Pokemon rather than having one of the first Pokemon and several of the second one (each Pokemon gets its own group).