When designing epics it's quite handy to write up requirements in Aha so there can be a high degree of clarity in what is needed to deliver the epic. Unfortunately these requirements never leave Aha which makes it hard to use them when GitHub is where your project's issues live.
Ideally requirements written in Aha will be pushed to GitHub and linked to the epic when the epic itself is pushed.
Thank you for your idea. Requirements are currently sent to GitHub either as issues or checklist items, depending on how you configure the integration. It would be possible to then link them to epics in ZenHub but this would be a manual process.
At this time, given the options above and other priorities, we are unlikely to implement an automatic link to ZenHub epics. We hope you understand.