Group 
Definition
A group combines routings according to user-defined criteria. Routings in a group do not have to belong to the same plant.
Use
When you create a routing, you can assign it to a group. You combine routings in a group that describe
Similar production processes for different materials
Different production processes for the same material (for example for various lot-size ranges).
Grouping helps you find routings later.
Note
When you maintain a routing, the system loads all routings belonging to the same group. You are, therefore, advised to combine only small numbers of routings into a group.
If you do not want to group your routings, you can let the system assign a group key when you create a routing. In this case, the system creates a new group for each new routing.