How to reference container hostname or ip from another container in the same ECS task in cloud formation

I'm trying to setup an AWS ECS cluster which has a single task that has 3 separate containers for prometheus, promscale, and prometheus-ecs-discovery.

I'm trying to figure out how to dynamically set the env var PROMSCALE_HOSTNAME in my prometheus container to either the hostname or ip of the promscale container as i'm ultimately using this value in a config file so that the prometheus container can talk to the promscale container.

Is there any way to do this or do I have to create a load balancer in my VPC to handle this?

PrometheusTask:
    Type: AWS::ECS::TaskDefinition
    Properties:
      Family: !Sub "${Stage}-prometheus"
      ContainerDefinitions:
        - Name: !Sub "${Stage}-prometheus-container"
          Image: myorg/prometheus:latest
          Environment:
            - Name: STAGE
              Value: !Ref Stage
            - Name: PROMSCALE_HOSTNAME # <-- I WANT THIS VALUE TO BE THE HOSTNAME OR IP OF THE PROMSCALE CONTAINER
              Value: !Sub "${Stage}-promscale-container"
        - Name: !Sub "${Stage}-prometheus-ecs-discovery-container"
          Image: myorg/prometheus-ecs-discovery:latest
          Environment:
            - Name: AWS_REGION
              Value: !Ref AWS::Region
        - Name: !Sub "${Stage}-promscale-container"
          Image: myorg/promscale:latest
          PortMappings:
            - ContainerPort: 9201