Run an Ansible task to all hosts if at least one of the hosts has a variable

I want to run a task to all hosts if at least one of the hosts has a variable “new_node”.
For example i have inventory

[all]
host1.example.net
host2.example.net
host3.example.net new_node=True

And if in one of the hosts has variable “new_node=True”
then run this task on all hosts

---
- hosts: all

  tasks:
     - name: Create file yep at all hosts
       file:
         path: /tmp/yep
         state: file

What condition or filter should i apply? Any ideas. Thanks