The current GroupedExchangeAggregationStrategy will combine a list of exchange instances for a given correlation expression and propagate the exchange with that list. This is great as long as users are content with processing the list of exchanges.
What about users that would like to extract data from the exchange and add that to the forwarded list? This is something that require users to create their own strategy.
What I propose is that we provide base class for users to extend such that it manages the grouped list and have the user state and return the type of instances that will be added to the grouped list.
I will attach a base class that users can extend and an example of a sub-classed version that will return a list of exchange instances like the default GroupedExchangeAggregateStrategy camel core class.