When you're working with many target shapes within a blend shape deformer, it can be helpful to sort them into groups for quick identification. For example, you have a blend shape deformer with target shapes that affect the mouth, but you want to create separate groups for the shapes that affect the upper lips and another group for the lower lip shapes.
You can then set the weight value for a group and key it to quickly animate that group of shapes - see Key the blend shape weights.
Likewise, if you have many blend shape deformers on a base object, you can put them into groups in the same way, such as several blend shape deformers whose target shapes affect the eyes and several blend shape deformers whose target shapes affect the mouth.
To create a group
Multiple target shapes must be under the same blend shape deformer.
A target shape cannot be a member of more than one group.
This creates a group containing the selected target shapes or blend shape deformers. When you group blend shape deformers, all their target shapes are included beneath them in the group.
You can create any number of nested groups.
To create a group with nothing selected
You can also drag and drop a blend shape deformer or target shape onto another blend shape deformer or target shape to create a group that includes these two.
To add members to the group
To rename a group
To reorder the members of a group
To remove a member from a group
To delete a group