(Naming is shitty) The idea is that similar to batch you can batch multiple calls together, but you are able to use outputs from the previous transaction as input for the next transaction. An output of a transaction is an event. So, if you have an event like this:

	Self::deposit_event(Event::<T, I>::Submitted { index, track, proposal });

You would be able to use index, track or proposal as identifier for the values to pass them into the next transaction. The identifiers and the values could be stored in the dispatch_context. It require changing the macros a little bit to generate some code that makes it easy to put the event into dispatch context. Otherwise it should be straightforward to implement.