An extension table containing mapping info for all
group to VCI (and VPI) mapping for 1 Scaling service.
This table is for create, delete 1 mapping entry.
Utilize atmxServiceGroup to create or delete a
1483 Scaling Service. Create 1483 Scaling Service
only with 1 group and 1 vc thru the atmxServiceGroup.
Adding or removing other group-to-vc mapping should
then use this atmx1483ScaleGroup.