Istio traffic routing with custom gateway

Is it possible to route traffic using ISTIO if I use a custom gateway (Azure App Gateway) instead of ISTIO’s gateway? Below is my use:

I have two different version of deployments (in kubernetes) running mapped to a single service. They are displayed accurately in the kiali dashboard. Now the problem is If I want to route traffic only to one particular deployment using virtual service and destination rule, I’m unable to do that.
Hence I want to know whether this case is possible at first place with custom gateway?

Why use a custom Gateway if the istio gateway works perfectly?
I work with Azure and my gateway has no problems.
You should use Istio’s

What gateway to use is a different discussion topic. My question is whether istio supports internal traffic routing even when using a custom gateway. Please let me know if you need any other details.