Change hierarchy of issue types to allow for more than just epics, stories, and sub-tasks. Include a layer between epic and story for feature.
If epic is a several months long project, then there can be multiple features within that, and then teams can write stories to build those features.
The feature should include feature link just like epic link.
Story would be linked to a feature. The feature would be linked to the epic.
This is useful for groups that want to scale Agile using Scaled Agile Framework (SAFe) or others frameworks.