Zend certified PHP/Magento developer

How do use dictionary variables from two sources in Ansible?

We have an Ansible script that sends an email when a server has been updated. In the script I want to to use variables from two different locations for the send to addresses. The first location is from the inventory itself and is called owner_email the second is from the vars section of the roles called mb_addresses. In the script I am trying to figure out how to set it up. The relevant section is this:

- name: Send the report
  mail:
    host: our.mailserver.com
    port: 25
    to: 
      - "{{ owner_email }}"
      - "{{ mb_addresses }}"
    from: Tower@thiscompany.com
    subject: Linux monthly patch results
    body: "{{ lookup('file', '/depot/reports/patch/{{inventory_hostname}}_patch_report.txt') }}"
  delegate_to: localhost
  become: no

In the main.yml of the vars section mb_address is set up this way:

mb_addresses: "first.email@thiscompany.com,second.email@thiscompany.com"

The problem with that is I get the first email but the second is ignored.

The same happens if I set it up like this:

mb_addresses: '"first.email@thiscompany.com" "second.email@thiscompany.com"'

I have tried it like this:

mb_addresses:
- "first.email@thiscompany.com"
- "second.email@thiscompany.com"

When it is done this way neither email is picked up.

What I am trying to avoid is to go into each inventory item and add in a stock group to receive the completion emails.

What am I missing?