I think I understand now.

Right now, the functionality you seek needs to exist in the module itself. I think what you are asking for is exactly how yum and apt work.

This can be added to basically any module, but then we also have to teach the module how to work with lists (like apt and yum are told they are special). It would be nice if the module itself could declare this versus the hard code, which is reasonable.

What load balancer are you using? (Or just the shell command?)

We could teach 'shell' to do "with_items" using the ";" as a seperator, perhaps.

I think you might be understanding it, just backwards. Switch around which
direction the list is going, and you'll have it. The module isn't accepting a
list, the command being run is getting one, maybe with a special variable.

Perhaps I can make it clear with a ridiculous example. Pretend that I work
just like ansible, and I have to help orchestrate a birthday party.

---
- name: Birthday party
  guests: Joe Jimmy John Susy our_kids kids_from_school
  tasks:
    - name: make somthing to eat
      shell: /home/prepare.sh --food cupcakes --food pizza --for ${guest_name}
      delegate_to: wife
      register: food
  
    - name: feed the kids
      action: feed ${food}
  
    - name: distribute pins for pin-the-tail-on-the-donkey
      action: give_pin

Here would be a good example of a chance for a special variable and a
"run_once" or "batch" option. I could call my wife and say, "Hi Honey, here is
who is coming to the party. It's just going to be Joe. Go ahead and get the
food ready". After she has ordered a small pizza, cooked one cupcake and cleaned
the kitchen, I call her, and tell her about another guest. I do the same
thing for every guest. She would most likely come at me with a kitchen knife when I
got home. If I could do something like the following, I think the party would
be a lot less stressful for everyone:

---
- name: Birthday party
  guests: Joe Jimmy John Susy our_kids kids_from_school
  tasks:
    - name: prepare somthing to eat
      shell: /home/prepare.sh --food cupcakes --food pizza --for ${everyone_who_is_coming}
      delegate_to: wife
      register: food
      run_once: yes

She could use the "everyone_who_is_coming" special variable, and only do the task once.
Hopefully that gives the idea.

This feels like complex_args to me and making a module take a list and knowing what to do with it, but I am closing this because we don't support cupcakes :)

cheribral, I will be glad to hear if you found a solution for this issue.