Cross namespace communication in GKE ingress

[ankita-1420]

Hey @liggitt,
We have two different applications deployed in two different namespaces in GKE, I am trying to expose this applications using GKE Ingress which is in the default namespace.
I have SSL certificates for this applications.
So the issue is external load balancer is not able to communicate with our applications because the namespaces are different.
Referring to issue no #17088 I found that Nginx ingress can be used in this case, but my use-case restricts use of Nginx or any third party tool, Hence can you help me to find a solution or any work-around for this using GKE ingress only.