The group parameter can be used to define the group owner of a file or directory. For example, let's say you are using the copy module to copy a file. In this example, the copied file (foo.txt) would be owned by the "wheel" group.

- name: "copy foo.txt to /tmp"
  copy:
    src: "foo.txt"
    dest: "/tmp"
    group: "wheel"

Here are the attributes of the copied file (foo.txt).

-rw-r--r--. 3 root wheel 4096 Jun 26 08:21 foo.txt