Use existing ALB with aws-alb-ingress-controller instead of creating a new one?

[Benjamin Smedberg]

The normal way for aws-alb-ingress-controller to work is that the controller creates the load balancer. But would it be possible to use the controller to add an AWS service to an existing load balancer and target group which is managed externally? We typically deploy our DNS and load balancers externally using terraform, and so we'd merely like to use the controller to map a target group to the particular nodes/ports that run a kubernetes service.