hostvars problem

hosts.ini

[dhcp_server]
10.14.66.2

[env_01]
10.14.66.11
10.14.66.12
10.14.66.13

[sql_servers]
10.14.66.11

[app_servers]
10.14.66.12

[wts_servers]
10.14.66.13

[sql_servers:vars]
ram_mb=65536
vcpu_count=4
slug=SQL

[app_servers:vars]
ram_mb=16384
vcpu_count=4
slug=APP

[wts_servers:vars]
ram_mb=8192
vcpu_count=4
slug=WTS

task.yml

- name: Provision SQL servers 
  vmware_guest:
    hostname: www.google.com
    username: bob
    password: "{{ vault_vsphere_password }}"
    validate_certs: no
    datacenter: BLAH
    folder: /SOME/FOLDER
    name: DEV-W19-{{ hostvars.slug }}-{{ env_number }}-66.2
    template: TMP-CENTOS7-MINIMAL
    datastore: SOME_DATASTORE
    state: present
    wait_for_ip_address: no
    hardware:
      memory_mb: "{{ ram_mb }}"
      num_cpus: "{{ vcpu_count }}"
  loop: "{{ groups.sql_servers }}"