Feature Request Summary: 

An API end point to list object records related to a target object.

Description/Use Cases:

For apps built on sunshine, accessing related objects is done through list related object records endpoint. It is great for this purpose. However, it is limited to listing related objects which are set as 'target' in the relationship type. A second endpoint to pull object record set as 'source' is needed.

A simple use case would be shared objects. Consider an object of type "meeting_room", "rental_car", or "server". There is a relationship type from "Zen:User" to each of these objects. You can easily manage them for a user by pulling all its related records from the endpoint mentioned earlier.

Now consider that some of these records can be related to multiple users. If an incident happens and you want to list all affected users, the logic will be more complex.

Also in case you want to delete an object, it would not be possible before finding all relationship records and deleting them. This is once again a more complex logic for records set as targets in the relationship and can take long time to process in client-side applications.

Business impact of limitation or missing feature:

The absence of this endpoint can be responsible for more complex client-side app, slower development, and degraded performance in custom apps.