Можно ли опубликовать общедоступный маршрут IP по Windows RRAS VPN?

Selectively routing traffic over a VPN is called split-tunneling. Your question could benefit from a bit more detail, or the caveats when answering become so many.

Perhaps you are looking for a way of inserting these networks into the client side routing tables (you need to describe your usecase)?

Then you could script the routing table entries on the clients yourself, or use CMAK to the same split-tunneling effect.