Chain tickets can be booked separately online, as per the train/station combo for the respective chain.
They can be booked as telescopic only @ PRS Counter. They are to guide/plan, in case no direct train ply in the route or CNF Ticket are unavailable in direct options.
The chain may or may not be telescopic.
As of now, chain are to get an opportunity...
more... as more option for same route, while later berth availability option may get merged along with chains!!