You are on the right track about hostvars.
This magic variable is used to access information about other hosts.
hostvars is a hash with inventory hostnames as keys.
To access fields of each host, use hostvars['test-1'], hostvars['test2-1'], etc.
ansible_ssh_host is deprecated in favor of ansible_host since 2.0.
So you should first remove “_ssh” from inventory hosts arguments (i.e. to become “ansible_user”, “ansible_host”, and “ansible_port”), then in your role call it with:
{{ hostvars['your_host_group'].ansible_host }}