We have seen use cases where the customer would like to have one portal which connects to multiple gateways, for example:
The customer has an internal (LAN) and an external (DMZ) gateway. The internal gateway only exposes internal APIs and the external gateway only exposes external APIs. An internal developer works with both internal and external APIs. Currently this means he will have to work with two portals or some of the APIs need to be available on both gateways. Both are not really ideal for security and/or usability.
The preferred solution would be that it would be possible to connect one portal to multiple gateways.