A SubItem has GroupID setting.

NOTE: For details on VCI SubItem component, refer to VCI VCI SubItem Component (VCISDK).

The GroupID is enabled in a VCI with multiple SubItems when the value is set to other than 0.

When a SubItem with a GroupID other than 0 is grabbed and the ownership is transferred, SubItems with the same GroupID will also have their ownership transferred. The default value is GroupID=0, which disables this grouping function.

The GroupID is used when a VCI has multiple SubItems and you want them to physically interact with each other.

As shown on the figure above, in the world of user B, the physics is just copied from the calculation result on the world of user A, therefore the ball does not move.
The stick that moved in the world of user A will cause the ball to move and the result of that calculation is copied to the world of user B, which causes a delay.

By hitting the ball (owned by B) with the stick (owned by B), as shown in the figure above, the physics behave correctly.
To recap, GroupID is used for transferring ownership of SubItems that are grouped with a SubItem that is grabbed by a user.

• Billiard. When you grab a cue, the ownership of balls also moves to you.
• Objects connected with Joints. When you grab a part of it, the ownership of all SubItems will be transferred to you