Custom adobe.io runtime domain name

[KimonP]

Currently, when configuring adobe.io (using AEM x CIF) endpoints for our application, we are using the "standard" adobe.io runtime endpoints. i.e. https://runtime.adobe.io/api/v1/namespaces/[...] We would like to mask these endpoints, using custom domain names. 

Can anyone shed some light on how we can go about this?

Kind regards