Hi Fernando Mendes, Andrea Rodriguez (CD Baby), Marco Diani, Jason Wong,

since we also have multiple brands, we were dealing with the same issue.

We created an app for us to solve this issue once and for all. If you want it too, check it out here: https://www.zendesk.com/marketplace/apps/support/261269/select-email-sender-address/

Here are some features we integrated:
- Automatically use the correct email sender, depending on the agent's user group
- Restrict sender email based on user-agent group
- Warn the user when submitting a ticket with the default address, if the default address is not allowed for his group
- Based on your sender address, specific Tags will automatically be added
- Search for the support address associated with your ticket
- Easy & fast – you don't need to scroll through the Dropdown

Feel free to try it for 30 days for free: https://www.zendesk.com/marketplace/apps/support/261269/select-email-sender-address/

If you want to automatically apply the correct brand signature to all of your emails you can check out:

https://www.zendesk.com/marketplace/apps/support/261268/1-click-mail-signature/

Let me know what you think or if you have any suggestions to improve it.