Execute handler only if another was not notified

[Nikolay Artamonov]

Hi guys!

Let's assume that we have simple playbook:

---
- hosts: server.com
  tasks:
    - name: Some task
    - ...
    - notify A
    - name: Some another task
    - ...
    - notify B
    - name: Some another another task
    - ...
    - notify B
  handlers:
    - name: A
    - ...
    - name B
    - ...

How can I ensure that handler B will be executed only when A is *not* planned?

Thanks!

-- 

Truly yourth,

Artamonov Nikolay