To configure an NSX edge gateway to be the egress point for a data center group, increase the scope of the edge gateway. The gateway then becomes shared across all data centers that participate in the group.
When you scope an edge gateway to a data center group, all routed networks that are attached to the edge gateway become attached to the data center group and scoped to it.
All new routed networks that you attach to the edge gateway belong to the data center group.
A routed network attached to an edge gateway which is scoped to a VDC can participate in a data center group only if the scope of the edge is increased to this data center group.