Targeting playbook hosts depending on host variable value

I have an Ansible inventory inventory.ini structured as follows (shortened for the example):

[prod:children]
prod_first_plateform

[prod_first_plateform:children]
database_prod_first_plateform
embedded_prod_first_plateform
ldap_prod_first_plateform
proxy_prod_first_plateform

[database_prod_first_plateform]
serverA team=developer
serverZ team=integrator

[embedded_prod_first_plateform]
serverB team=integrator
serverY team=integrator

[ldap_prod_first_plateform]
serverC team=developer
serverX team=integrator

[proxy_prod_first_plateform]
serverD team=developer
serverW team=developer

The requirement is as follows:

I would like to use this inventory in different contexts:

To target all of my servers (with hosts: all)
To target a specific platform (with hosts: prod_first_plateform, in this example)
To target machines belonging to a specific team (depending on the team host variable, while adhering to this inventory syntax, without adding a new host group.

My issue lies with this third point.

My idea would be to use a syntax which works in my playbook like hosts: all[team=developer].
I know this syntax doesn't work, but I try to found a correct way to achieve that.

Is this currently possible with this inventory?

Solution

You can use the group_by module in a preliminary play in order to create yourself groups from a variable.

Given:

- hosts: all
  gather_facts: false

  tasks:
    - group_by:
        key: "hosts_of_team_{{ team }}"
      when: team is defined

- hosts: hosts_of_team_developer
  gather_facts: false

  tasks:
    - debug:
        var: ansible_play_hosts
      run_once: true

Running it on your inventory, the second play would yield:

ok: [serverA] => 
  ansible_play_hosts:
  - serverA
  - serverC
  - serverD
  - serverW

As expected, since we are targeting the hosts where the variable team equal developer via hosts: hosts_of_team_developer.