Can I load balance between different servers with caddy?

Question

I'm trying to load balancing with Caddy. I want server A to be in charge of more requests and server B to be in charge of fewer requests.

With Nginx, load balancing by server weights is possible as in the example below.

http {
    upstream backend {
        server A.example.com weight=5;
        server B.example.com;
    }
}

But I'm not sure it is possilbe with Caddy too. How can I set Caddyfile??