Is there a way to link multiple testing branches name with AWS ALB target groups?

I'm currently attempting to set up a DevOps environment for testing multiple developer github branches with container. I choose AWS ECS for container orchestration service. However I encountered an obstacle: how to access multiple testing branches via url corresponding to its branches name: For example:

http://branch1.abc.com --> ALB target groups "branch1" --> AWS ECS service "branch1"

http://branch2.abc.com --> ALB target groups "branch2" --> AWS ECS service "branch2"

...

http://branch50.abc.com --> ALB target groups "branch50" --> AWS ECS service "branch50"

We have daily about 50 branches for testing in parallel.

Besides,I have successed to create AWS service discovery(AWS Cloud Map) private dns name for accessing each aws ecs fargate instance's private ip with route53:

route53

But it is ok for office internal network testing, if some deveplopers want to test via internet, we need the ALB... Actually I don't know if there are other ways to approach.

Do you have any idea about this?