"We need to show quotes related with the current document."
This user story will cause many of our subsystems to get modified, and it is more or less 4-5 sprint length. Splitting it into sub stories is impossible cause the modifications has no business value. But, in the 5th sprint, there will a business value.
What do you suggest? How are we gonna create business value, demonstrate it to our customers each sprint and also let our customers to prioritize work on each sprint?
Make your team create the tasks needed to complete the "show quotes" story.
Make these fine grained enough that several of them potentially fit into a sprint.
Put all of these in a separate backlog.
Have the team, not the customer, prioritize this backlog, and cluster tasks with high coherence into chunks.
These chunks go into the project backlog as "reduction of x% of work left to complete 'show quotes'", or a similar formulation quantifying the benefit this item will bring in terms of expected progress towards the goal.