n electricity distribution networks, spot network substations are used in interconnected distribution networks. They have the secondary network (also called a grid network) with all supply transformers bussed together on the secondary side at one location. Spot networks are considered the most reliable and most flexible arrangement of connecting power to all types of loads. Switching can be done without interrupting the power to the loads.
I assume you mean this?
You would probably have to contact the utility to see if they would allow backfeeding the mains through this type of system...
The only restricted Grid Tied location that I am aware of in Northern California is in downtown San Francisco. There, they interconnect several power networks together, and monitor to prevent backfeeding of power.
If a Grid Tied system was installed (of sufficient size), the backfeed of the GT Solar could look like a backfeed between utility feeds--tripping their protection circuits.