Multiple configurations for vhosts when using ejabberd with the mod_post_log module

Question

I'm currently trying to get ejabberd working when using the mod_post_log module. I have defined two virtual hosts and I want some vhost-specific module configuration. My approach is the following in the ejabberd.yml file:

append_host_config:
  "host1.com":
    modules:
      mod_post_log:
        url: "http://host1.com/ejabberd_post_message"

append_host_config:
  "host2.com":
    modules:
      mod_post_log:
        url: "http://host2.com/ejabberd_post_message"

I expect this to work but it doesn't. According to the logs, mod_post_log cannot find the url option.

It works fine however if I define the following in the ~/.ejabberd-modules/mod_post_log/conf/mod_post_log.yml:

modules:
  mod_post_log:
    url: "http://host1.com/ejabberd_post_message"

But this only works for one host.

So I'm not sure why the approach I tried is not working. Is there anyone who can clarify this and see what I'm doing wrong? I believe that I'm defining two seperate configurations for the mod_post_log module but apparently there's something incorrect here.